Part 2: TRS 80 Model 4 - Fixing the power supply and writing TRS-80 disks

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  • Опубліковано 25 січ 2025

КОМЕНТАРІ • 213

  • @andykopgod
    @andykopgod 3 роки тому

    I know nothing about computers, but im.watching this at 1am, from good old UK 🇬🇧 and im hooked. 😄👍

  • @F4LDT-Alain
    @F4LDT-Alain 5 років тому +62

    Awww... no part #3 indeed. That's frustrating. It was getting so good.

  • @PaulinesPastimes
    @PaulinesPastimes 5 років тому +29

    Did I miss Part 3? I was waiting to see what you managed to do with this computer. I love all-in-one designs like this. Cheers.

  • @antonnym214
    @antonnym214 5 років тому +1

    I worked at a Radio Shack Computer Center at this time. The DOS that came with the model I, 3, and 4 was TRS-DOS, and was pronounced "triss-doss" and there was also an after-market dos called NewDos by Aparat; which was virtually identical, but provided some enhanced commands for File I/O and a built-in keyboard de-bounce routine. NewDos was practically mandatory on model 1s, due to the bad keybounce. Great Vid!

  • @billreyna1355
    @billreyna1355 5 років тому

    I used to work on older TRS models. They were unique but again at the time there were many PC or office systems vendors. Tandy did in-house repairs but the quality wasn't always there. Glad you got something to work.

  • @mrlurchAU
    @mrlurchAU 5 років тому +54

    Still waiting for part 3..... 😂

  • @YesterGearPCii
    @YesterGearPCii 7 років тому +1

    I just love old Tandy machines. I have a 1000-RLX-HD "B", and a 1200-2FD. Always looking for an old Model 4 to add to the stables. Great to see another one brought back to life!

    • @BlackEpyon
      @BlackEpyon 7 років тому

      Tandy 1000HX and 1000RSX on my bench. These are my babies :)

    • @lowellturner7012
      @lowellturner7012 6 років тому

      great job. if I remember and become more active I will share tales of my TRS-80 M4 (and my need to get rid of it) but I have way too much stuff going on (legal - (civil)- crap) that are only allowing short times on the internet. Probably good for me after discovering the geeks that can remember the original movie Karate Kid.

  • @johanlaurasia
    @johanlaurasia 6 років тому +3

    I started out on the Model I and have worked on every model (pre PC models), so Model 1,2,3,4,12,16 and the color computer line as well as the MC-10. Few things to mention. First, you can hold down break and turn the power on, the moment the power is on, you can release break and wait for the CRT to warm up and you'll see Cass? appear. Also, if it's on, there's no need to turn it off. If you're booting to a non-disk setup, and the unit is on, you can hold break and simply hit reset instead of powering off and back on. Lastly, and most important, I cringed each time you powered on with the disk in and the door closed. Easy way to fry a disk, I'm surprised you didn't. Best practice is to insert the disk, but leave the drive door open, then power on, and while the drive is seeking to zero, you can immediately close the door after power on and it'll boot to disk. Several OSs out there that will work, TRSDOS, CPM, LDOS, NEWDOS/80 to name a few. The system also supported 4 drives, and since the machine was designed for two full height drives, you could actually get 4 1/2 height drives mounted in the system which a lot of people did in later years when the 1/2 heights became available. NEWDOS/80 supported pretty much anything, you could manually configure number of sides and tracks for each drive, and specify 5 1/4" or 8" drives. In more recent times, there are things like FreHD that emulate drives, but store data on an SD cards. You could probably put every Model 1/3/4 program ever made on a single SD card. My friend bought a 4P to (lug) to college with him. Nice, portable version of the 4, still had to be plugged in, and was still quite heavy, but basically the same machine. I think the only thing it lacked was a cassette port.

  • @tiggjj
    @tiggjj 6 років тому

    Boy this brings back memories. I started with a model 1 back in the very early 80s. I still have a model 100 that I haven't used in ages. I used to write assembly language programs for the model 1. I spent almost a decade with Tandy computers including the model 2000 and one of the later 1000 series that had windows. Glad to see one working these days!

  • @DerekWitt
    @DerekWitt 3 роки тому

    On my Model III, I actually used floppies sold for IBM PCs.
    My Model III ran quite nicely with those floppies. Both LDOS 5.3.1 and TRS-DOS 1.3 formatted them without a hitch.

  • @blautens
    @blautens 5 років тому +3

    I see you have some images to make DOSPLUS disks for your Model 4. My older brother was one of the 3 people who started Micro-Systems Software back in the 1970's - they were the authors and publisher of DOSPLUS (along with BBS-PC, M-Term, and other popular software). Since I basically was his shadow since I was 9 years old, my career was predetermined - my first paying job there was in 1979, as I recall - I got paid 10 cents per disk to make all the media - which I did at home. Along with that I got to keep the computer at the house, a tricked out Model I with 4 disk drives, a Holmes speed up kit, and custom software (naturally) to make 3 disks at a time from one master, very quickly. I could make $40 a night at home making the disks, labeling them and stuffing them into the giant 3 ring binder with the documentation, which was pretty good for an 11 year old. By the time I was 13 or 14 I was working tech support, which sounds ludicrous, but remember the guys who started the company essentially barely finished high school when they started the company. So a 14 year old who knew assembler and ate, slept, and breathed TRS-80s and that software was actually in a pretty good spot to help people. And actually the bulk of tech support was done via USPS. Yup - people actually wrote letters.
    The company had more money than most people that age should, so besides crazy amounts of company cars there was actually a retail store they owned in West Palm that was a real Tandy dealer - you could buy your TRS-80s there (along with other brands), and yes, they were a bit more flexible than buying a TRS-80 at the Tandy owned stores - so you'd get a tricked out computer with badging that seemed a bit confusing, much like the one in this video. We were still friends with the guys at the "legit" Tandy stores - hell, back then, the community was so small, we were all friends. Moving from Hollywood to Boca Raton made it easier to make the leap to writing for IBM PCs later on, probably too late, but things changed past even that, and Steve wasn't a fan as I recall - and the switch to focusing on Amigas was long after I had moved on to college and then more "corporate" computing endeavors (as did my brother, eventually). But 40 years later, even as I toil at Citrix, I could still trace my roots (and even some others at Citrix) to the people there in the small circle of tech wonks in Boca, where Scott Adams was arguably a bigger deal than Bill Gates was. (How's that for a deep cut?)

  • @jeffk5724
    @jeffk5724 6 років тому

    Something to try. Get one of your 5 1/4 floppies and a hole punch. Opposite side of the side notch punch twice to mimic a notch. Flex it open and punch a seek hole in the same place the other seek hole is. Viola. You can now write to both sides of the floppy. All my disks were modified this way.

  • @ramdileo
    @ramdileo 5 років тому +5

    1:14 actually... I'm amazed ... of how clean is that board.. and the CRT.. and the rest........ not FAN that introduce dirt inside there .. I suppose...

  • @ridiculous_gaming
    @ridiculous_gaming 5 років тому

    I just ordered a (to be fixed) model 4 with the original black and white looking one. Nothing shows up in the monitor by the seller, but I am hoping that it is fixable. I would like to mention how amazed I am to see how hardy this machine looks. Looking at the age of these vintage computers and how hardy they still are simply drops my jaw. My first contact with a computer was in 1984 while attending basic computer programming in grade 9. This is the reason why I am still so interested in these computers even today...I can't wait for this ebay purchase to arrive. The shape of this computer of yours? It looks fantastic for something so old.

  • @infinitecanadian
    @infinitecanadian 7 років тому

    Glad to see this. Finally, your vids are at the top of my recommendations again. I used to volunteer to take things apart for a charity to recycle them. I cannot count how many things I recycled, but now I regret doing so, because some of them at least might have been classics, although most of them were not working.

  • @TheLawrenceWade
    @TheLawrenceWade 5 років тому

    Really nice score! I'm glad you're saving it - and its box! Kudos to Radio Shack (may you rest in peace) for the great stuff you once sold in every town.
    The loose connection to the monitor - I don't see "blooming", which is where horizontal and vertical deflection are both affected at once, usually also affects high voltage supply and therefore CRT focus. This really only looks like it affects vertical deflection. Look at the capacitors in the monitor board, especially around the power supply and vertical output circuits. And yeah, reflow every solder joint on everything bigger or hotter than a 1/2 watt resistor. The vertical movement you're seeing represents a fairly large change in current to the vertical output stage as you wiggle the wires, so there's a fault that really needs to be found and fixed.
    Something is still wrong in your CRT blanking circuit; your retrace lines and raster shouldn't be so prominent. And you've complained that the brightness isn't what you expect (but that's subjective - I remember these machines when they were new, they weren't really bright, you weren't looking at JPEGs). So, what affects vertical deflection, brightness, and causes retrace lines? Make sure you have the rated voltage to the monitor's board. Is the filament power coming off the flyback? And then, after that, use an ESR tester on any capacitor even remotely near a heat source. I wouldn't want to re-cap that whole computer, it's a museum piece and has good brand caps already. Let's just make sure it works, and save all the old parts in a baggie in the chassis so that they'll be available if it ends up in the Smithsonian.
    Just take your time and relax. This computer knows it's in loving and caring hands and it wants to be fixed. If you've done a few repairs, you know when a machine is working with you on the repair. Quality parts, quality design, pride in construction, luck and human respect in the life that it's had, and then there's a certain other factor.... It just WANTS to work, and you can feel that in your gut.
    Lawrence Wade
    Ottawa, Canada

  • @Nf6xNet
    @Nf6xNet 7 років тому +3

    If I am not mistaken, the "deleted data" message in IMD is referring to sectors which use the "Deleted Data Address Mark" (DDAM) instead of the regular address mark. I believe that at least some of the TRS-80 disk formats used DDAM on the directory track sectors. In other words, these are normal, esoteric, low-level details about the formatting used in a particular image, and not something to worry about. Congratulations on your progress fixing up your Model 4!

  • @BrainSlugs83
    @BrainSlugs83 5 років тому

    I learned to program BASIC on a model 4. To go to model 4 BASIC, hold down the orange reset button while it boots up (instead of break). Also some disk games put out audio on the cassete tape interface (you'd have to connect a speaker to it to hear), but it was pretty great. Also the printer port, even though it's a weird card edge connector, the port was a centronics port that was compatible with pc printers (though radio shack made a really cool daisy wheel printer, that basically worked like a fancy type writer).

  • @dunebasher1971
    @dunebasher1971 6 років тому +3

    Here in the UK, the TRS-80 wasn't that common. I bought one from the USA on eBay about 18 years ago (the shipping was a killer), expecting to have to run it off a step-down transformer, but on opening up the case I saw that there was a jumper on the PSU for switching between 110V and 240V. I wonder if that was the more expensive Astec board mentioned in other comments? All I had to do was switch the jumper and replace the US 2-pin plug with a UK 3-pin one, and it worked perfectly on native 240V AC.

  • @RE1974
    @RE1974 7 років тому +23

    Great couple of videos, good to see this old system coming together. Just a few comments... your system has the horrible Tandy-designed lower-cost power supply which was marginal and problematic when new, and nowadays most exhibit the problems yours shows. Tandy wanted to reduce costs so instead of buying the bullet-proof Astec (save for the Rifa caps) designed their own low-priced turkey. It was so bad that a tech bulletin from Tandy expressly forbade using this low cost PSU in Tandy hard drives due to the variable nature of it's output. Tandy used this PSU and when it ran out during production would begrudgingly install the more expensive Astec, which is why in US M4s you sometimes see the Astec. Also if the computer went back under warranty with a failed PSU they would install the Astec, or if you walked up to RS National Parts to order a M4 PSU you were invariably sent an Astec.
    Your machine is also interesting because its a non-gate array (PAL) system, but has the Phillips 12VCMP31 CRT and membrane keyboard which were sold with the 4GA. Its possible that this was such a late production PAL M4 that TCA had run out of white 12VCMP4 tubes and the ALPS keyboards typical of the PAL systems, or more likely the keyboard stopped working at some point and again at the time if you want to RS National Parts asking for a Model 4 keyboard and they had no ALPS keyboards on hand you had no choice but to put in the crappy membrane 4GA keyboard, which was not a big deal since it fits and works.
    I hope that when you remove the RFI shield you find a hi-res board, indicating you have a fully maxed out M4, but if you don't find one remember I make and sell HRGs :-)

    • @kennethbouchard8643
      @kennethbouchard8643 6 років тому

      All maufacturer are cost cutting. Consider this machine sold for $2000 back in 1984. That would be like $8000 in todays cost, and really was not that powerful a machine. Z80C was the last generation of Zilog Z80, which boosted its native speed to a whoppling 8 Mhz? I recall having a Z80B in my Model 1 and with the flip of a switch you could run everything at double the speed. But you had to flip it back to low speed to load programs in from tape or disk.

  • @melkiorwiseman5234
    @melkiorwiseman5234 5 років тому

    "Dry" solder joints weren't restricted to any particular manufacturer. I can remember seeing a repair guy struggling to fix a Commodore 64 which would keep on rebooting whenever you moved it.
    I got him to let me take a look and I quickly spotted that the solder joints all around the power connector were very dodgy. When he re-soldered those joints, the rebooting problem stopped.

  • @kaczan3
    @kaczan3 5 років тому +8

    I can't find Part 3. Was it not made?

  • @datsun210
    @datsun210 5 років тому +2

    Wake me when part 3 is ready.

  • @rodmandealerman3297
    @rodmandealerman3297 5 років тому

    Wow, very nice job! I remember using a Model 2 back in high school (1979 if memory serves). My partner in crime would dictate from the book of programs, and I would type. No floppy drives, no tape. Ugh. I don't remember the name of the game we played, but I do remember the name 'Jovian'. Could have been us, or the enemy. The playing area was just a grid of dots. I believe the up arrow was our ship, and the enemy was the @. Good times.

  • @offperception
    @offperception 7 років тому +1

    Very interesting video! Certainly teaches quite a bit about where to look for issues with old computers.

  • @geoffreed4199
    @geoffreed4199 5 років тому

    there was an upgrade/fix tandy put into some model iv's with 12v issues, it was a seperate powersupply specifically for the floppy disks. i had one at one point with a tandy installed aux power supply for the drives.

  • @kennethbouchard8643
    @kennethbouchard8643 6 років тому

    Looks like you got it mostly fixed. If you find it has ripple of the display, I had replaced the main 220UF cap in my Model 4P which cured that. I also cleaned controls, and resoldered all the pins. Its normal for age to oxidize, and crack the solder joints from heat over time. Just resoldering all the power supply stuff usually works. Power supply is the hardest working part of the computer.

  • @tony359
    @tony359 5 років тому +2

    did reflowing the main output connector fix the low 12V output when disk drives were being accessed?

  • @sonofeloah
    @sonofeloah 5 років тому

    Considering that there had been some component replacement on the power board, I would have gone and replaced ALL of the caps and would have checked the resistors. Also would have checked and maybe replaced the VR components as those tend to go kaput if there have been any issues with the power board before. Worth the work in the long run.

  • @wonderwond
    @wonderwond 6 років тому

    THE GOOD ole days, use to play on those suckers for weeks on end programming a game or two,, many time flies

  • @johnathanstevens8436
    @johnathanstevens8436 2 роки тому

    I replaced the RIFA and reflowed the connectors and it started right up. Interestingly enough the machine had a power supply used more for the 4P but it seems to be an original 4 with the blue CRT and discrete logic chips. I had my fill of deskmate and multiplan so I bought one of Ian Maveric's hi res graphics boards so I could watch fractals and play Reversi.

  • @XLessThanZ
    @XLessThanZ 4 роки тому

    I'm not good at the PCB repairs, but it's good to learn off of your experiences...Thanks

  • @bonobo8803
    @bonobo8803 5 років тому +10

    Only 26 days left to make part three within a year of part 2.

  • @naderhumood
    @naderhumood 4 роки тому

    Thank you very much Adrienne.... V informative. ✌️🇧🇭 Waiting for p 3

  • @DANBED20021
    @DANBED20021 6 років тому +1

    is there a part 3 to the TRS 80? I can't seem to find it on UA-cam! Maybe UA-cam creators can start putting links to their previous post in the current post and then in the previous link to the following posts? I just get frustrated when I get into a video and then I can't find the next set of videos that goes into that particular series!

  • @Cpt_Adama
    @Cpt_Adama 2 роки тому

    I would seriously recommend making a dim bulb limiter for testing old equipment so that a cap short doesn't take out your transformer and other items along the way. You got lucky here but that could have been a disaster causing major and possibly unrepairable damage.

  • @coryengel
    @coryengel 7 років тому +19

    Great job. Thanks for editing out the lulls. A tip: train yourself to look at your camera lens and not your screen. Watching videos of someone looking at their screen is like trying to have a conversation with someone who insists on staring at my left ear.

    • @IanRomanick
      @IanRomanick 7 років тому +4

      I was going to say the same thing. It was a really good video otherwise... waiting for part 3. :)

    • @RachaelSA
      @RachaelSA 6 років тому

      Yeah, i noticed that too, but, the left eye (his left) seems to be looking at the camera, the right one seems to be looking at something else?

    • @TheOcculus
      @TheOcculus 5 років тому

      @@RachaelSA He probably has a "lazy eye". It's inherited. I got it from both parents. When people notice it... it seems to make them uncomfortable. It's only folks that I interact with a lot that notice this.
      I have high functioning Autism too, according to the tests. I don't usually look directly at people and that really makes people that don't know me uncomfortable.

    • @DonnyHooterHoot
      @DonnyHooterHoot 5 років тому

      Ohh Mr. Director! LOL

  • @75slaine
    @75slaine 5 років тому +2

    Did you ever do part 3 ?

  • @bobdole57
    @bobdole57 4 роки тому

    So I learned a few things about TRS-80 disk images, maybe you've also discovered but I'd figure I'd report here.
    The DSK and DMK files that ImageDisk is able to convert are all DMK formatted disk images. The ones that don't work (and are usually smaller in size) are JV1 or JV3 formatted DSK files that ImageDisk can't deal with.
    There is a way to deal with them though. David Keil's TRS-80 Emulators, he has ones for the Model 1, III, 4/4P and CoCo have special files that let the virtual disk drives in the emulator use a real PC drive. So you can mount a DSK and a real disk in the emulator and using TRS-DOS, LS-DOS, CP/M or Disk Basic on the CoCo, you can duplicate the mounted image to a real disk. You can also use native TRS-80 disk duplicating software like Super Utility as if you were on a real machine. I had been using the IMD method myself, but I had a lot of images I was unable to write and the emulator method basically solved all the little issues I was having.

  • @thedungeondelver
    @thedungeondelver 7 років тому +5

    I remember some of the TRS-80 IVs at school (in 1988!) had that "flicker on drive activity" intermittently. I always assumed it was the monitor wigging out because of the drive motor's magnetic interference :P

    • @kennethbouchard8643
      @kennethbouchard8643 6 років тому +3

      The drive motor ran at a constant speed. It was the fluctuation of the underpowered supply. Bad weak caps, causing spikes and noise.

  • @sypodj
    @sypodj 6 років тому +2

    Great job! Love how big the parts on the boards are 🖒

  • @AndyGarton
    @AndyGarton 6 років тому +2

    Was there a part three for this please?

  • @kaiyoshi2243
    @kaiyoshi2243 7 років тому +12

    Love the video. Just a friendly tip.... Don't turn on or off the TRS-80 with the disk drive door closed. You will zap the disk. I'm kinda surprised it didn't happen during the video. My TRS-80's will zap a disk every time, like clockwork.

    • @kennethbouchard8643
      @kennethbouchard8643 6 років тому +4

      I have turned mine off with the doors closed, disk in, never had prioblem. But do not do that while the drive is running. If yours is zapping the disk, you may also be victim to the mains cap weak. That causes spiking in the power supply, as it is a switching supply. So result is the voltages spike on the 12v and -12v areas.
      That causes FDD to send data spikes to the drive.

    • @MickeyMousePark
      @MickeyMousePark 5 років тому

      I was a Tandy Computer Center manager in the 1980's..there was a Tandy Service bulletin that came out that said exactly what you said..what happens is on power on the floppy drive 0 head is energized and does a write for a split second then steps the head to 0 then checks for write protect then it does the same for drive 1...it all depends where the head is when you power up...if it is at track 0 or track 17 that would cause the most problems ...anywhere else on the disk the CRC would be able fill in the missing byte of data...
      The Model I said to put the disk in and turn on the power
      The original Model III owners manual said to put the disk in and turn on the power (copy and paste from Model I manual). It was corrected on later revisions
      Even some of the software said to put the disk in and turn on in their owners manuals..Most likely a copy and paste from Model I
      RE: The Model I did not have a model number on it it only said TRS-80..With the expansion unit you could hook up to 4 floppy drives

  • @JohnJones-oy3md
    @JohnJones-oy3md 7 років тому

    Great series! I'd love to see the floppy drive servicing. IIRC, I had to send my old 4 back to RS for realigning the drives at least twice. Can't remember what exactly caused the issue - seem to recall it was something stupid I did, like trying to read tracks beyond the floppy's capability in some sort of disk software. Super-Utility maybe?

    • @kennethbouchard8643
      @kennethbouchard8643 6 років тому +1

      Old floppy drives used a metal band that was the head stepper. If the head jammed, it would bend the metal strip, and ruin the drive. You could never get it to align right after that happens. The drive belts also could be replaced, but you discover with age, that they deteriorate, and get soft and gummy. That causes the drives to not run at a proper speed, fluctuating, and just useless. Most drives had the 60 cycle squares to help calibrate the speed using a neon bulb. There used to be calibration disks, using a decent oscilloscpe to align the stepper motor to get proper signal. But seldom did they get that bad.

  • @jeffk5724
    @jeffk5724 6 років тому

    I had the Model 4P portable. Upgraded the RAM to 128K myself. It had the Model 3 boot loader disk to get into the Model 3 mode. It looked like a sewing machine with it we all stuffed into it's case. Miss the DOS game named Springer.

  • @Daveyk021
    @Daveyk021 Рік тому

    Adrian, is there anyway for you to put that conversion software and disk writing software up? The old sources seem to be gone.

  • @CmmdrKitty
    @CmmdrKitty 4 роки тому

    I just picked up a 16 k model 3 no drives (floppy) installed. I need to replace my single yellow brick before it also spiews. But I cannot find the cap i need anywhere. I can find a 100v 0.1uf cap but i need 250v and dont wanna wait 2 months to get one. Any good places to buy power supply caps?

  • @SmalltimR
    @SmalltimR 5 років тому

    fascinating restoration - enjoyed watching

  • @joelavcoco
    @joelavcoco 7 років тому

    I had the same filter cap burn on my Model 4 just a few weeks ago, but I haven't ordered a replacement yet. When I do get around to fixing it, I'll check for bad solder joints as well. Great video.

  • @thesmallestatom
    @thesmallestatom 7 років тому +2

    Love your dedication and skill. Maybe I would like to see some solder reflow shots. Also, the lower end trs80's.... Trash80. Lol.

  • @anoopsahal1202
    @anoopsahal1202 5 років тому +2

    Do you ever repair , eg re-cap, in situ, or is this a “no, no”. ( I have never done any electronics)

  • @SidebandSamurai
    @SidebandSamurai 5 років тому +21

    Chanting
    Part 3 ... Part 3 ... Part 3 ... Part 3

  • @JustWasted3HoursHere
    @JustWasted3HoursHere 6 років тому +1

    Did you say there was going to be a part 3 to this?

  • @thomasbrasse3145
    @thomasbrasse3145 6 років тому

    I had that exact same computer. I learned basic with it. Good memories.

  • @steveoerkel735
    @steveoerkel735 4 роки тому

    The Rifa was very common in the past, especially in DUAL Record-Players. In cause, that the Powernet has slightly risen in Europe from 220V +-10% to 230V +-10% has blown that things earlier as in the US.

  • @jessenone3708
    @jessenone3708 6 років тому

    hey i have a NEC 425 ready es. It worked until the battery went dead, so i put it in the attic and it's still there. I think it has windows 2.1 or something like that on it.

  • @cpcnw
    @cpcnw 6 років тому

    Coolio! Only comment - if you are going to use a pointer please use a plastic one - waving screwdrivers around mains voltages & eht's makes nervous lol!

  • @mohamadasriabdulazid4784
    @mohamadasriabdulazid4784 5 років тому

    I have facing 12volt reel problem before in switch mode power supply, it begins with voltage just over 11 volt, after couple month, the diode in 12volt reel is die short. Anyway nice video.

  • @sniperneil53
    @sniperneil53 5 років тому

    Do you have an ESR meter for testing caps? A cap can look ok, but it can still be leaky. An ESR meter will tell you what the Equivalent Series Resistance of the cap is and if it is out of spec (or close to it's max value), replace it as it is bound to fail in short order. An ESR meter can save a lot of the time and effort of you having to revisit the power supply to fix it again.

  • @williamsquires3070
    @williamsquires3070 7 років тому

    Those caps must be replaced with the proper X/Y-rated safety caps, or left out. The safety caps are designed to fail open, and not catch fire or smoke (like yours did). Old tube radios and TVs sometimes had these across-the-line caps for the same reason. If you can afford it, replace any old 85c rated caps with modern 105c rated ones from Nichicon, Rubycon or Panasonic. Those old electrolytic caps can leak, or fail outright and stink up the place, too!

  • @FullMetalFab
    @FullMetalFab 4 роки тому

    No part three ? Did you sell the TRS80 model 4 ?

  • @hussssshie
    @hussssshie 5 років тому

    On these old power supplies the best you can do is to replace all the electrolytics. Even if they aren't bulging or leaking electrolyte, they tend to become a load instead of a capacitor even if their capacitance looks fine when you test it, it's not under voltage. In some cases under voltage they turn into a resistor that pulls the regulators down, often killing the regulator as well.

  • @thenoid5131
    @thenoid5131 6 років тому

    One thing I learned working as a tote man is that those pins in those molex connectors get weak and thus create a gap between the rail pin and the receiving female pin on the connector cable leaving just enough space for micro arcing to occur please look at the plastic and if there's browning that indicates a bad spaced arcing molex which will create crazy stuff like intermittent blackouts or unwanted reboots and shutdowns

  • @samsulummasamsulumma6898
    @samsulummasamsulumma6898 7 років тому +1

    Glad you succeeded. Keep up the good work sir.

  • @benbaselet2026
    @benbaselet2026 6 років тому +2

    Those X2 rated caps tend to lose value over time, they just wear out, even the good ones do. It's a good idea to measure the uF value before putting them in.
    Also the 0.01 vs. 0.1 uF should not make much of a difference, mostly a frequency response thing. Definitely no sparks should fly because of that as long as the voltage rating is sufficient and it seemed to be at 275 VAC. I suspect the part was already bad or maybe it got too hot or physically damaged during the replace.

  • @winstonsmith478
    @winstonsmith478 6 років тому +2

    Where is part 3?

  • @mrlurchAU
    @mrlurchAU 6 років тому +1

    Did you ever finish off this job?

  • @kenkobra
    @kenkobra 5 років тому +1

    What happed to part 3?

  • @samuellourenco1050
    @samuellourenco1050 5 років тому

    A 10x bigger filter capacitor won't break the PSU. Also, it shouldn't blow or spark like the one you placed, unless it is bad or is not rated for that voltage. As for the electrolytic capacitors, doing a recap may be not prudent at all, and actually can cause more harm than good. Anyway, nice video!

  • @ssfn1_
    @ssfn1_ 5 років тому +18

    PART 3 NOW!

  • @Zankuho
    @Zankuho 7 років тому +1

    Any chance to see some software for this OS in part III?

  • @twopointfiveltr
    @twopointfiveltr 6 років тому +1

    Where is the part III video? You should get a cassette drive and some games for this

  • @iliketurtles4869
    @iliketurtles4869 6 років тому +2

    Part 3?

  • @mariodistefano2973
    @mariodistefano2973 5 років тому +1

    fantastic restoration!!! professional!

  • @TedSchoenling
    @TedSchoenling 5 років тому

    How many times did you zap yourself on the high voltage caps that you never mentioned to discharge?

    • @SuperVstech
      @SuperVstech 5 років тому +1

      Adrian Black any progress on the part 3 video? HAPPY NEW YEAR!
      Lemme know if you need any new in box 5-1/4” disks...

    • @SuperVstech
      @SuperVstech 5 років тому

      Adrian Black stacks of drives also...

  • @johnny14794
    @johnny14794 5 років тому

    Been waiting for part 3 @_@ Please come back with part 3?

  • @Krivulda
    @Krivulda 7 років тому +1

    You need to use type X caps, do you know that? Type X across the AC, type Y from AC to ground.

  • @Walczyk
    @Walczyk 4 роки тому +1

    what happened to part 3!!!!!!!!!!

  • @tamphex
    @tamphex 6 років тому

    I remember playing Star Trek & using a biorhythm program (and believing the results as an impressionable kid at the time) on this computer. Good memories.

  • @Membrane556
    @Membrane556 6 років тому

    I had one of those kind of caps die on a IIe and I got a replacement out of an old inkjet printer PSU I had in my junk box that just happened to be the same value.

  • @TheSaabClinicUK
    @TheSaabClinicUK 7 років тому +1

    If you make a note of what pins output what voltage. You might be able to squeeze in a modern PC PSU and wire that to work.

    • @johnpossum556
      @johnpossum556 7 років тому

      Good thought but I wonder if the newer PSU noise will be problematic? I once wired a 120VAC B&W CRT television into a car and when it ran the noise was so horrible I had to go buy a noise suppressor to get it all to work properly. The outputs of SMPS are also inherently very noisy. Be good to run a test before cutting any wires on the old PSU harness first.

    • @electronash
      @electronash 7 років тому

      Adrian Black
      If you want a decent modern open-frame PSU, I would recommend something like a Meanwell or XP Power.
      Those can be a tad pricey, but often way better built than the average ATX PSU.
      You don't really see ATX PSUs with both the -5V and -12V rails any more either, so might be better to just re-cap the original PSU, of buy a good arcade PSU.
      The original one looks to be in condition though, and will probably be OK now that you've reflowed the dry solder joints.
      You don't always have to recap the entire PSU either, just the caps whos capacitance has dropped and / or ESR is increasing.
      Those $15 component testers are actually fairly accurate btw. Easily good enough to see if any caps are bad.
      Keep in mind that most cheap testers don't auto-discharge caps, so be sure to short them out just before testing them.
      (and always check the voltage across the main reservoir caps before working on a PSU.)
      For people on a budget (replacing multiple larger electrolytics can add up) - even if you just replace the smoothing caps for the +5V and +12V outputs, it would extend the life of the old PSU a fair bit.
      Nice vid btw. ;)
      Always interesting, clearly explained, and well-shot.
      I've been wanting to do my own vids for over four years now, but I can't quite get over the fear factor of speaking on-camera, even just a narration. lol

    • @electronash
      @electronash 7 років тому

      Adrian Black
      The vid does remind me that I do tend to clean the connectors on retro machines as a matter of course.
      That type of Molex connector are fairly notorious for getting bad contact as they get older.
      The contact area of the pins / plug is often very small, and any slight corrosion can quickly get worse on the higher-current rails due to the heat.
      I often do the extra step of lightly scraping the surface of all the pins (but watch out for dry joints after), then use contact cleaner or just IPA for a final clean.
      (also be careful not to let the microscopic metal shavings from the pins get anywhere else but on a bit of cloth during the final cleaning.)
      The pin / plug corrosion is very common on machines like the Dreamcast, where the higher resistance causes boot problems, resetting, or a blank screen.
      I've also seen many of the plugs on ATX PSUs with the crappy "gold" plating get so bad that it starts to melt and char the plastic housing, and could feasibly cause a fire. :o
      (hate those 4-pin Molex power splitters btw. Most of them are evil. lol)

  • @michaelmaciejewicz7534
    @michaelmaciejewicz7534 6 років тому

    I have a box in opened 1.44 disks do you want them

  • @VSigma725
    @VSigma725 7 років тому

    Is that a Packard Bell on the desk next to you? 486 era Packard Bells loved that vertical 3.5 floppy drive.

    • @stargazer7644
      @stargazer7644 5 років тому

      486 Packard Bells were the biggest turd ever laid. They were the bane of my existence in the 90s after our IT guy got a "deal" on a bunch of them from Sears.

  • @michaelperugini4199
    @michaelperugini4199 7 років тому

    so i am not clear, did you use a 1.2MB floppy drive using the dmk2imd and just changed those settings , or did you use a 350K drive and change those settings?

  • @reh3884
    @reh3884 7 років тому

    I wish I had to skills to maintain all my old machines. I had a couple Model Is, a III, and a IV, plus an Apple IIe. I gave them all away awhile ago because I couldn't service them. I'm a software guy!

  • @Captain_Char
    @Captain_Char 7 років тому +1

    I use an HXC floppy emulator on my Kaypro 2x which uses CPM 2.2u as its operating system, I believe the TRS 80 can also run CPM. however I choose a floppy emulator over original disks for stability and longevity, as a 256mb sd card is now my A and B floppy drive and it will load all disk images natively though the pc program for the hxc

    • @ChrisGuiver
      @ChrisGuiver 7 років тому

      yeah, montezuma cp/m 2.2-2.4 were available, and tandy sold a cp/m 3.0. i preferred the 2.x. (diffs between 2.2 to 2.4 were minimal)

  • @minutemark
    @minutemark 7 років тому

    It would be prudent to avoid touching the contacts of those capacitors on the bottom of the board. I didn't have one of these, but I did have a TRS-80 Pocket Computer that I got used the same year this computer was built.

  • @HiddenPalm
    @HiddenPalm 7 років тому +1

    YOURE A FREAKING MANIAC!!!! I LOVE IT!

  • @jamescorvett
    @jamescorvett 7 років тому +1

    i remember these dinosaur machines from 1979-80. my very first pc that i learned to code on. things sure have came a long way since then.
    And isnt that a metal plate under that PSU? Sure looks like a nice place for a short.

    • @kennethbouchard8643
      @kennethbouchard8643 6 років тому

      RFI shield mostly needed to make it compliant for RF interference reasons.

    • @stargazer7644
      @stargazer7644 5 років тому

      It isn't a metal plate, it's a plastic insulator under the power supply. And TRS-80s really aren't called PCs.

  • @rich1051414
    @rich1051414 7 років тому

    What kind of switches are those in that keyboard? Sounds like SKCC alps.

  • @britsluver
    @britsluver 5 років тому +1

    Part 3 please

  • @jonathankent5898
    @jonathankent5898 5 років тому +1

    Where's part III?

  • @jessedunn3766
    @jessedunn3766 4 роки тому

    Still waiting for part 3. :(

  • @IDPhotoMan
    @IDPhotoMan 4 роки тому +1

    Please part 3? :-)

  • @SuperHaunts
    @SuperHaunts 7 років тому

    I'd LOVE to find an image of NEWDOS80.... Any ideas?

    • @jimdeane5050
      @jimdeane5050 7 років тому +1

      www.trs-80.com/wordpress/#

    • @jimdeane5050
      @jimdeane5050 7 років тому +1

      Left side, scroll down, under "Services".

  • @Laceykat66
    @Laceykat66 7 років тому

    "Yanked it out, very easy"
    Oh shut up.
    I can't solder a drop on my workspace. You make it sound so easy.
    How many times have I cried as I BROK the part I was trying to remove. Too many times to count mister !!!
    (Really, I am ALL thumbs)
    You are so brave.

    • @kennethbouchard8643
      @kennethbouchard8643 6 років тому

      Despite solder suckers and removers, I usually had best results just with small pliers and heating and plucking. Less heat means less damage.

  • @flybobbie1449
    @flybobbie1449 7 років тому

    I'm impressed by the video camera you are using to film this, what is it.

  • @cummerunited8103
    @cummerunited8103 5 років тому

    OK, this is weird: Three people at least have asked about a Part three, and those comments have a blue "View reply from Adrian's Digital Basement". But when I click that, nothing appears; the blue simply changes to "Hide Reply". Replies from other people to other comments show just fine, but after three tries to read it I still don't know what happened to Part 3, as the replies are invisible!

  • @johnpossum556
    @johnpossum556 7 років тому

    About the monitor ...the lines you see that go diagonal are called retrace lines. I forget which stage is most likely responsible for this but I know I used to know it. ha! (there is a certain voltage level which must be brought low in order to tell the raster to stop during the time it retraces back to the left side of the screen) It's a very typical problem for aged CRT circuitry to have. Hopefully I've given you enough info to google it from there.
    About the PSU ... even though you can't see signs you most likely have leaky caps. They might feel hot or warmer than the others. Sometimes they will show on a FLIR camera but in general its just better to replace all those. Come to think of it Mr Carlson's Lab has some really good vids on leaky caps and a unit to help detect them.
    My best advice would be I would not run that PSU (unless on a current limiting circuit which you should get if you're getting into doing these routinely!) until you get it fixed because it may be running under a bigger load (due to the current running through the caps which is why the voltage output is low) than you realize and often when these things go it is a cascade failure meaning it blows a whole lot of other parts with it that are currently OK. Cascade failures are NOT fun.
    Good video, though! It's fun to see a younger generation get into using the computers I grew up using. I might even get inspired enough to dig mine out of storage sometime but with all this wonderful new tech I really doubt it.

    • @johnpossum556
      @johnpossum556 7 років тому

      High internal resistance is OK. You are looking for low internal resistance which will act like a unnecessary load on the output of the PSU. Quite a bit of current can be travelling through those caps. They essentially become resistors as they age.
      ua-cam.com/video/lLQThhf3Brc/v-deo.html

    • @kennethbouchard8643
      @kennethbouchard8643 6 років тому

      Its the G2 grid voltage of the picture tube. Same as analog TV sets. The lines, are the deflection from bottom to top, thus the word retrace. Normally it is blanked out by a diode, but if overdriven the raster, then that is the result. Any TV with a CRT is or can be overdriven to cause this. Some tv sets had a sub brightness control to counteract that effect.

  • @johnparadox9429
    @johnparadox9429 7 років тому

    Interesting, as I had a TRS-80 Model 3 [8" disks! still have some of them] and even the triple external drive. Long lost, however, but I loved the keyboard I replaced on it because it had caps lock ND shift lock [e.g. 1 became ! without having to press shift.] I still have several Coco's 2 & 3, status unknown until I get all my shelving up - have almost every addon for the Coco.

    • @SuperHaunts
      @SuperHaunts 7 років тому

      Models 2 & 12 had 8 inch disks, not model III....

    • @kennethbouchard8643
      @kennethbouchard8643 6 років тому

      Model 2 systems had the dual 8-inch drives. They used those because they were meant to be business computers, and thus to be able to store more information per disk. Aside from ZIP drives, They never really got beyond 2.88 MB 3.5" floppies. Of which 1.44 reamined the standard for HD disks for a very long time.

    • @MickeyMousePark
      @MickeyMousePark 5 років тому

      @@SuperHaunts Also Model 16