I worked for JVC(UK) from 1985 to 2016, originally as an engineer, then TLO, then Assistant Technical Manager, then Technical Manager, then Technical Marketing Manager. The microfiche manuals were mainly for internal use, but were distributed to a few of the bigger service outfits who had the capability to read them, mainly Mastercare. They were only available for a short time - between the end of paper manuals and the start of manuals being distributed on CD-ROM, which in time was replaced with online distribution. Pretty much everything that was on microfiche was also distributed on the early CD-ROMs in PDF format, so they may already be out there somewhere. Obviously finding them may be tricky after 30 years.
Did you get involved in the design of the dynamic drum system at all? We are looking for someone to help bypass it at the chip level or at least mimic it so the chip thinks it's still working and replace the DD head with a non DD one.
Hi Colin, sorry if you've discussed it in a previous episode, but figured I'd mention: For getting digital audio off of a MiniDisc, there has been substantial progress with the Web MiniDisc project to let a modern PC interface with a NetMD recorder. Originally it was to allow you to copy content easily to an MD, but now there's the capability to export the audio off of a disc as well, fully digital, directly as a file to the PC. Maybe this would be worth looking into?
@@video99couk Captures off home recording equipment can be a challenge, thanks to the efforts of the RIAA and the "Home taping is killing music" people. Back in the day, deck-to-deck was often hampered by SCMS. There are devices that do conversion between formats (coax and digital, sample rate) and also offer SCMS stripping, so you can send your copy-protected digital audio from a CD to a DAT to an MD or whatever else. Downloading direct from a pre-HiMD disc results in an ATRAC file that may not sound as good when converted in software on your computer (Sony doesn't offer any software to do this; it's all community-provided) vs. pulled into your computer's soundcard as a bitstream and saved as a WAV (or whatever target file type).
Tips for taking apart these power supplies: 1. Examine the gaps at the mains connector and the output cable, find suitable tools that fits the gaps (strong, but thin screwdriver usually needed) 2. Then put the PSU in the freezer for at least an hour to make the glue/weld more brittle 3. Immediately after removing the PSU from the freezer, put it on a solid surface and tap along the joint of the plastic housing with the edge of a smaller hammer, until you hear cracking sound 4. Insert the previously selected tools into the gaps at the mains connector and/or output cable strain relief, and pry it apart. After finishing the repair, I used to glue them together with superglue.
I recognise that power supply. I bought a bunch of them from AliExpress, all the same design and identical label to the one you have. Some of them were behaving weirdly so I opened them up. Of the ten I opened, there were four different designs of PSU inside and evidence that they were basically old random PSUs hacked out of other devices/bricks and shoved together in a hurry. So who knows what the faults might have been - worn out caps, not originally rated as per the label etc. Bin them on sight would be my recommendation!
Regarding your concerns about that audio transformer, I'd surmise that its specs are not at all critical, and that the cheepo one would work just fine!
I´ve worked on many dynamic drum machines. These days I just remove the system, take out the gears and leave just the core with worm drive that fools the optical sensor. Done. The biggest issue is that the worm gear is cracked in almost all cases (and it jams). Dealing with this is just a pain but I still do it.
I wish there had been a channel like yours when I had bunch of ailing U-wrappers they might have been easily fixed and they were ToTL decks. When we moved had to throw the whole lot away....hmmm on second thought even if they were working I dont think they could have fit on the lorry, it was already jam packed! Heavy bastards they were too.
Dynamic tracking control with Piezo element, I have it on my Betacam SP BVW 75 without having experienced problems with dynamic tracking, but it is probably also a somewhat higher quality
If the picture is normal on increased speed play, however small the increase, I guess 150% of normal speed? Actually, it looks good on any faster speed, the machine has a jog dial. And it is normal on slo-mo, but falls apart in normal play, what would you reckon the problem might be? Thanks.
When I lived in England I had a few large (>1000kVA) step-down transformers to run various 110V devices. Oftentimes (but not always) when I turned on one of the transformers, it would pop the circuit breaker. I assume that breaker was sensitive (it was usually the same one) and the large sudden load caused the trips. I imagine that's what your RCD saw - a load spike, not a short to ground. Too bad both the built-in fuse and the RCD weren't enough to save your equipment.
If you don't mind a bit of desoldering, you can get free signal isolation transformers out of obsolete network gear. Technically I think these are 110 ohm, and balanced, but I haven't had any trouble putting SPDIF through them. You could add a CCTV balun to make it a better match to 75 ohm coax, they're a quid each or less.
If the shutdown is random it usually is the DD system, Other permanent faults would cause permanent shutdown, I had two similar machines and one of them developed a random shutdown and bypassing the DD system did the trick.
Another very informative video. Colin, I don't suppose you have a Sony SLV-SE720 laying around (or maybe someone else does)? It's a pretty low end VCR. Mine suffers, as do many, from corrupt 24LC08 EEPROM data and rather than throw it away I am searching the internet for the contents of that chip so that I can manually re-program it. There is a way to re-initialise it from the unit, but my buttons are all so wrong due to corruption that I can't find the right one to get into test mode.
For reading the JVC microfiche, a school or collage library might be able to help. They usually have a microfilm machine. When i was at collage 18 years ago they had a microfilm machine in the student library.
Might be worth checking libraries for the microfilm. The main central libraries round here all have microfiches with attached laser printers. No idea how much they charge for printing though.
The primary snubber capacitor probably failed then the switching transistor probably shorted, which shorted the rectifier and blew the tracks and fuse.
I think it might well be repairable. But I won't, it's not worth the expense or risk. If it were in some rare and precious audio/video equipment, then I would.
JVC's BR- S525U Variable Tracking System With conventional tracking systems, video tracks can only be correctly traced during standard speed; during still and slow motion accurate tracking cannot be maintained and noise is produced. To avoid this problem, JVC's automatic variable tracking system was developed to precisely trace the track at various speeds. To accomplish this, the new system incorporates a photo sensor to detect the proper head position and a moving-coil actuator to change the head position of the two pairs of precision- machined VT (Variable-Tracking) heads. Better head-to-tape contact, greater accuracy, and higher resonance frequency than comparable systems are attained.
I worked for JVC(UK) from 1985 to 2016, originally as an engineer, then TLO, then Assistant Technical Manager, then Technical Manager, then Technical Marketing Manager. The microfiche manuals were mainly for internal use, but were distributed to a few of the bigger service outfits who had the capability to read them, mainly Mastercare. They were only available for a short time - between the end of paper manuals and the start of manuals being distributed on CD-ROM, which in time was replaced with online distribution. Pretty much everything that was on microfiche was also distributed on the early CD-ROMs in PDF format, so they may already be out there somewhere. Obviously finding them may be tricky after 30 years.
Did you get involved in the design of the dynamic drum system at all? We are looking for someone to help bypass it at the chip level or at least mimic it so the chip thinks it's still working and replace the DD head with a non DD one.
The best way to get those PSU s apart is put them in a vice and listen for the cracks. See big Clive.
Hi Colin, sorry if you've discussed it in a previous episode, but figured I'd mention: For getting digital audio off of a MiniDisc, there has been substantial progress with the Web MiniDisc project to let a modern PC interface with a NetMD recorder. Originally it was to allow you to copy content easily to an MD, but now there's the capability to export the audio off of a disc as well, fully digital, directly as a file to the PC. Maybe this would be worth looking into?
Got me thinking now, if any of my MD recorders are netmd. I think one might be.
@@video99couk Captures off home recording equipment can be a challenge, thanks to the efforts of the RIAA and the "Home taping is killing music" people. Back in the day, deck-to-deck was often hampered by SCMS. There are devices that do conversion between formats (coax and digital, sample rate) and also offer SCMS stripping, so you can send your copy-protected digital audio from a CD to a DAT to an MD or whatever else. Downloading direct from a pre-HiMD disc results in an ATRAC file that may not sound as good when converted in software on your computer (Sony doesn't offer any software to do this; it's all community-provided) vs. pulled into your computer's soundcard as a bitstream and saved as a WAV (or whatever target file type).
Thank you Colin for the advise and a Merry Christmas to you and the family. Cheers
That PSU must have made a hell of a bang when it went. LOL.
In the middle of the night, we didn't hear it.
@@video99couk I'm surprised no one woke up from the bang considering how bad the PCB looks.
7:27 I may have been watching too much Big Clive - I half expected "One Moment Please..." followed by the results of off-camera violence...
Tips for taking apart these power supplies:
1. Examine the gaps at the mains connector and the output cable, find suitable tools that fits the gaps (strong, but thin screwdriver usually needed)
2. Then put the PSU in the freezer for at least an hour to make the glue/weld more brittle
3. Immediately after removing the PSU from the freezer, put it on a solid surface and tap along the joint of the plastic housing with the edge of a smaller hammer, until you hear cracking sound
4. Insert the previously selected tools into the gaps at the mains connector and/or output cable strain relief, and pry it apart.
After finishing the repair, I used to glue them together with superglue.
I recognise that power supply. I bought a bunch of them from AliExpress, all the same design and identical label to the one you have. Some of them were behaving weirdly so I opened them up. Of the ten I opened, there were four different designs of PSU inside and evidence that they were basically old random PSUs hacked out of other devices/bricks and shoved together in a hurry. So who knows what the faults might have been - worn out caps, not originally rated as per the label etc.
Bin them on sight would be my recommendation!
Regarding your concerns about that audio transformer, I'd surmise that its specs are not at all critical, and that the cheepo one would work just fine!
I´ve worked on many dynamic drum machines. These days I just remove the system, take out the gears and leave just the core with worm drive that fools the optical sensor. Done. The biggest issue is that the worm gear is cracked in almost all cases (and it jams). Dealing with this is just a pain but I still do it.
Over at VH in my thread "the ultimate guide to bypass the DD system" someone posted a fix for the cracked worm gear.
I wish there had been a channel like yours when I had bunch of ailing U-wrappers they might have been easily fixed and they were ToTL decks. When we moved had to throw the whole lot away....hmmm on second thought even if they were working I dont think they could have fit on the lorry, it was already jam packed! Heavy bastards they were too.
Dynamic tracking control with Piezo element, I have it on my Betacam SP BVW 75 without having experienced problems with dynamic tracking, but it is probably also a somewhat higher quality
If the picture is normal on increased speed play, however small the increase, I guess 150% of normal speed? Actually, it looks good on any faster speed, the machine has a jog dial. And it is normal on slo-mo, but falls apart in normal play, what would you reckon the problem might be? Thanks.
We had an HRD-540 at home! the RCU for it was like a foot long cos it had the LCD for Video+ recordings and whatnot.
When I lived in England I had a few large (>1000kVA) step-down transformers to run various 110V devices. Oftentimes (but not always) when I turned on one of the transformers, it would pop the circuit breaker. I assume that breaker was sensitive (it was usually the same one) and the large sudden load caused the trips. I imagine that's what your RCD saw - a load spike, not a short to ground. Too bad both the built-in fuse and the RCD weren't enough to save your equipment.
If you don't mind a bit of desoldering, you can get free signal isolation transformers out of obsolete network gear. Technically I think these are 110 ohm, and balanced, but I haven't had any trouble putting SPDIF through them. You could add a CCTV balun to make it a better match to 75 ohm coax, they're a quid each or less.
If the shutdown is random it usually is the DD system, Other permanent faults would cause permanent shutdown, I had two similar machines and one of them developed a random shutdown and bypassing the DD system did the trick.
Another very informative video. Colin, I don't suppose you have a Sony SLV-SE720 laying around (or maybe someone else does)? It's a pretty low end VCR. Mine suffers, as do many, from corrupt 24LC08 EEPROM data and rather than throw it away I am searching the internet for the contents of that chip so that I can manually re-program it. There is a way to re-initialise it from the unit, but my buttons are all so wrong due to corruption that I can't find the right one to get into test mode.
I don't think I have one of those but will keep an eye out when I'm searching my store room for something next week.
@@video99couk Very kind of you thanks. There may well be other SLV-SExxx models with the same EEPROM and possibly the same programming.
For reading the JVC microfiche, a school or collage library might be able to help. They usually have a microfilm machine. When i was at collage 18 years ago they had a microfilm machine in the student library.
They probably still have them but the ones I've seen were only readers from back in the day, without any scanning capabilities.
Would it not be possible to simply use a home flatbed scanner that can scan slides or negatives to scan those?
Probably not enough resolution, but I could try that.
I used to own a Panasonic AG-1950, Dynamic heads on Standard VHS. nice machine but did not have s-vhs, also would not play LP speed.
Might be worth checking libraries for the microfilm. The main central libraries round here all have microfiches with attached laser printers. No idea how much they charge for printing though.
I really want them scanned directly to high quality PDFs.
Yikes thats quite a blow up
The primary snubber capacitor probably failed then the switching transistor probably shorted, which shorted the rectifier and blew the tracks and fuse.
It would be repairable.
I think it might well be repairable. But I won't, it's not worth the expense or risk. If it were in some rare and precious audio/video equipment, then I would.
JVC's BR- S525U Variable Tracking System With conventional tracking systems, video tracks can only be correctly traced during standard speed; during still and slow motion accurate tracking cannot be maintained and noise is produced. To avoid this problem, JVC's automatic variable tracking system was developed to precisely trace the track at various speeds. To accomplish this, the new system incorporates a photo sensor to detect the proper head position and a moving-coil actuator to change the head position of the two pairs of precision- machined VT (Variable-Tracking) heads. Better head-to-tape contact, greater accuracy, and higher resonance frequency than comparable systems are attained.
I have this model but it does not work
Are we talking about the SVHS machine? It's probably got a problem with the Dynamic Drum gears. Watch this channel for an update to solving that.
Invece di sentire te si sente la traduzione italiana
Hello Colin, i have send you a e-mail for the S/PDIF Transformer.