Vintage amp repair - 04 FIXED!!!
Вставка
- Опубліковано 27 гру 2015
- I have finally managed to fix my troublesome vintage Marantz amplifier! Watch the video for more details! :o)
Marantz Repair Part 01: • Vintage amp repair - 0...
Marantz Repair Part 02: • Vintage amp repair - 0...
Marantz Repair Part 03: • Vintage amp repair - 0...
Marantz Repair Part 05 (setting the idling current)
Marantz PM350 service manual download link: www.eserviceinfo.com/downloadsm/21105/_Marantz%20PM350.html
Helpers and advisers:
Audio Amplifier Servicing: / @audioamplifierservicing
Dr Cassette: / @drcassette
Pavle Pavlovic: / dedskin1 - Наука та технологія
![Lp. Последняя Реальность #107 РОДНОЙ ДОМ [Финал] • Майнкрафт](http://i.ytimg.com/vi/IK3QKzKUlHM/mqdefault.jpg)
Hello, i want to thank you for your videos and the troubleshooting process. It helped me to fix a bad contact issue on the left channel.
I noticed the electric power was not stable between Q729 and Q731...and thanks to the service manual and your advice, i located the component and found a bad soldering on the emeter ! Now it’s fixed and my PM310 amplifier is saved for a couple or year hopefully 😊
NICE TO SEE WOMAN doing electornic things !!! REALLY NICE !!
Right, I keep losing my reply to this so here goes again. Try Fazio Electrics, ua-cam.com/channels/WODkkyItzvmQF-JTycUFow.html or Fran Blanche ua-cam.com/channels/MLgHbpJ8qYqj3CkdbvC0Ww.html
I enjoy your videos Maddi. Thanks.
Very interesting videos good vintage collections
What a smashing repair :-D, i like how you never gave up, i hope it's still working two years after your repair :-D.
Well worth the battle :-D
That final faulty transistor had something to do with the final output bias, without it there would have been some distortion.
Thank you! :o) Indeed it was worth it and still going atrong, though I think it's about time I check the idling current again, i'm noticing it getting a little warm more than usual :o)
Thanks for the info on the faulty transistor, I was baffled as to what that was.
The amp is now snuggly in my new system :o)
ua-cam.com/video/-hb2MFsLsng/v-deo.html
Perhaps you can run the transistors with a little less bias current, it may help the transistors to stay a little cooler.
If you go too low in current then it will distort, your ears are far better than test equipment.
Anyway smashing repair, never give up :-D
Hi congratulations on finding the defective transistor, once you have replaced the transistor you need to set the idling current as per the service manual. Ensure you have no input signal connected and no speakers or head phones and the volume control is set to minimum and balance set to centre. Do the procedure for both channels as you have replaced all the Electrolytic capacitors in the Amplifier and also due to the age of the Amplifier the idling current will have changed over time.You can do an initial adjustment when you first power up the Amplifier and then leave the Amplifier on for 20 minutes and readajust. Be careful when connecting you probe leads as its very easy for the probe to slip and short out one of the transistors, small hook clips would be better rather than the probes of the multimeter. You may also want to clean the user controls if they are noisy with Servisol Super 10 switch cleaner.I wish you well with you electronic projects and servicing, you have a natural curiosity and a sense of adventure when working with electronics which is great to see, all the very best
+Audio Amplifier Servicing
Thanks for the explanation as to why it still works even without the transistor, by what you said i'm glad I decided to try it at a low volume with not so precious headphones, both channels sound great though by instinct (or call it paranoia) I didn't leave it on for too long. Before going any further I will have to wait for the transistor to come from China, two week wait grrr, but all will be worthwhile in the end. Thank you again and happy holidays :o)
How many watts is your amplifier ms lemon.Great video!Cheers/Rob
This one, It's 38W per channel and you can call me Maddi :o)
Saludos
I tried to write Maddi but I was not sure if I was spelling it right so I did not.
But now that I know I will.
Have a great day Maddi :-)
Saludos/Rob
congratulations to revive this amp :-)
+Ramas Ramzetti
Thank you! :o)
Great work! A nice little amp. Very popular in the 1980's. You probably find it will work without that transistor but distortion will be high.
+Simon Spiers
Thank you! Yes I did notice that it worked without the transistor which confused me. I'm not sure what the transistor does exactly.
It's quite an ordinary "Lin" topology power amplifier. Q727 is a "driver" transistor for the "output" transistor Q731, which takes care of the negative part of the waveform. Likewise Q725 is the driver for Q729, which takes care of the positive half.
You can think of it as Darlington pairs if you like, with Q725/729 forming an NPN Darlington, and Q727/Q731 forming a PNP Darlington.
Likely you heard some audio with the missing transistor but it would have been distorted, as it would have been missing the negative half of the waveform.
Thanks for sharing! Your giggling is very cute. :-) I applaud your efforts to fix your electronic problem!
well done great amp why u get both sides working now is the live side f the channels are a loop so if u find the positive u get both sides working but its not true stereo but as long as u dont push the volume up too much it will be ok its like connectting the speaker wires at the back the one side positive wire to the other one thats how it works in the board same all electrics work on loops a tip to know enjoy your hifi ive got a cambridge its 1980s one i got it at a rumage sale in a church had three knobs missing its 800watts rms per channel and there 4 ive blown two pairs of speakers didnt realise it was that powerfull lol got 1970s celeston 15inch bass speakers 800watts power and tweeters in industrial stage boxes my msses hates them and a16 bar x2 graph just a old pioneer 1980s i find it funny my friend spent £4000 uk pounds on his system new but it still dont sound as good as mine he hates it too
nice!
Yes a lady into hifi wow 👌
It's easier with a digital scope to follow the signal. This was my second amplifier in 1981. i have now only the right knob and vu-meter...in a box.
Hey well done to you. I also have an amplifier (Aiwa XA 006k) that has problems and you have inspired me to try to fix the fault.
The fault is that sometimes one of the channels starts breaking up in the sound. If I give the amplifier a nudge it then sometimes starts working again. I am hoping that is just a dry joint. However, I think that it may be probably a capacitor that has dried up or something similar as it is an old amplifier.
I used to have that lubricant stuff that you could spray on the pots to help them to work correctly. I am thinking that this may fix the problem. I brought some from a shop on Edgware road in London a few years back. However, the shop is no longer there and I have lost the aerosol can that I purchased many years ago when I was more into electronics than I have been recently up until now lol .
Any help would be so greatly appreciated. I may post a video of me trying to fix it but I am shy lol :)
+Daniel Mitchell
Hey Thank you! :o) As for your amplifier, Is there a crackly sound like someone's scrunching newspaper? Try not to give the amplifier a nudge, you may nudge something else out of place lol. I know which aerosol you have, it's a switch cleaning lubricant: www.ebay.co.uk/itm/Super-Servisol-10-Switch-and-Contact-Cleaning-Lubricant-/300946300533?hash=item4611cc1e75:g:dFsAAOxyUylTWRbn
Start with spraying all the switches and pots, the input selector, volume control, balance, eq. etc...also any little variable resistors on the circuit board. As you said it may help. If that doesnt work it's time to find and download the service manual and investigate further.
Always start small, the worst thing is when you've gone deep, started doing big things and it was something very small that was the issue (i've done this before in the past and learned from it lol). It seems to be a very nice amplifier by the way.
You may not believe me when I tell you this, but i'm very shy too lol, each video I post here I struggle as i'm not used to this but Im trying to push myself. Give the video a try, it would be interesting to watch and easier to learn from one another through videos :o)
Maybe it's a transistor and another component failed on the left amp, which caused it to fail when it could have survived without the transistor anyway. Maybe it was there just there as an additional feature to kick in when another component fails, kind of how we have two kidneys, but can manage fine with just one. Just a thought.
Great projects you have on your channel.For some reason vintage amps sound a lot better than newly produced ones i think down to the digital processing they use.I still enjoying listning to music with my technics 1210 prefer the sound to cds and of course mp3 which is pretty aweful.
+Retro Hawk
Thank you! And you'd be right, 15 years back I foolishly got sucked into the digital age completely (i'm not anti-digital but selling my analogue equipment was the foolish part). I find it more enjoyable listening to vinyls on my Technics 1200 through this amp than mp3s. I'm glad we still have the technics turntables, they stopped production and are extremely expensive from what i've seen.
Your welcome.Yeah same here i do like aspects of digital such as portability but the sound its just not as enjoyable as you say.Good news few weeks ago technics announced it will be bringing the turntable back into production.Bad news is they will be priced around £3000 i was thinking going for then until i gasped at the price.
+Retro Hawk
ffffffff! £3000?!? What's with that price?! Now i'm really grateful I still have mine, I know I enjoy records very much but I could never justify spending that much!
lol I know its a silly price does look nice but not for that price.I still have the MKII models and they do me just fine albeit probably in need of a service.I need to pick up a decent amp at some point im using powered speakers at the moment and at low volume can hear the psu buzzing away.
I have a NIKKI vintage reciever it is in a nice cosmetic condition and have a really nice sound, but it has a problem, after some 10 minutes of playing the left channel sounds distorted....I need help,
Hi very impressed. Have just ordered some switch cleaner as you mentioned from your comments.. I have an old Cambridge audio A1 amp. Great sound from right channel. But very low sound left channel. Intermittently left channel kicks into life. Any suggestions would be very welcome. I tend to fix things on my motorbikes so tinkering electronics is not my usual arena. Thank you in advance and keep up your entertaining videos.
I do have a similar problem after recapping my 1977 hitachi trk 5280e cassette recorder.There is a sound for like a minute or so ,and then little by little the sound from the left channel disappear?!? I desolder both transistors left and right, but they are ok,so I don't know what to do now.If someone can help me with advice I'll be very grateful!
This sounds a little like a capacitor issue, is your cassette recorder recapped? something is messing around with the bias of a transistor maybe? i'm not sure 100% what it is, but just what it seems like.
It maybe an idea asking somebody on here: www.tapeheads.net/
I replaced all electrolitic capacitors,they was almost my age 😀.The rest are ceramic ,and they look ok,no cracks or something. Thanks for the link .This cassette recorder brings back memories from my childhood, my father use to have one😀
i would check the power channel caps or the diodes
The reason your left channel quit / hummed is that resistor was shorted. It would work without that resistor just like the right is but neither side will work right without that resistopr
Do you repair much with chinese transistors ?
I want to buy mj15022 and mj15023 from aliexpres but many people say there are fake ? What do you think ?
Stick with original parts as much as possible
You better be aware of the capacitors. They only discharge over er periode of time, hart to tell how long it takes. You can harm yourself severely touching them, when they are charged.
I must have at least 100 + vintage receivers.. Time to sell or give away a few.
Nice! I just imagined your place as a vintage amp museum.
lol its way to much. Ive got to get rid of some. Also have storage aeras full of vintage stereos and speakers.
+yupimbackk
your cave of vintage wonders would make a cool video, shame I cannot vlog it lol..Be sure to keep the best of your rare treasures!
I might be interested in buying a unit or two. Please contact me as I would like to know what you have
I'd like one 1979 Telefunken MA-1 please.
Hahahaha you just made me laugh oh dear... go and buy another transistor 4 christ sake.
BTW good work. lol
lol thank you, I actually got a few in the pack :o) ...Mind you hmmm i'm not sure exactly where they are at the moment :oO
So,it's like taking one kidney out. Your body still work? I joke but got a laugh from you. So if you find a replacement transistor and solder it in you will have 2 kidney,I mean 2 resistors again?