Advice & thoughts on DIY Recap/Restoration of vintage amp/equipment

I’ve done tube amps. I’d be reluctant to do sand amps. It you zap the transistors, you’re going to hurt. You could buy a working one on ebay.

I have done tuner, RTR, tubed preamp, never attempted on ss power amp, need some additional courage for that, but not in the need at the moment.

Is it worth the effort? Absolutely if you know what you are doing and not go crazy.

@noromance The amp works fine except for the occasional signal loss in the right channel. I'm thinking it's just a loose connection but since I'll be in checking contacts, I thought I'd recap since the caps are over 40yrs old. If the issue persists then it's not a big deal for me outside of the parts.

@petg60 working with capacitors doesn't scare me. The main thing is checking to make sure they're completely discharged before working on them and of course making sure you're not plugged in!

Did you make use of any special equipment on your SS repairs outside of a volt meter and soldering tool? I'm king of at odds about spending a $100 on parts to 'upgrade' the amp vs. finding a new amp altogether and just retiring the Adcom

@bipod72,

no use of special equipment apart from vm and soldering tool. Of course both the rtr and preamp were checked on oscilloscope later. Tuner not yet.

Fix the problem first, then recap - otherwise you concatenate possible problems making it even more difficult to fix.  Also, I would make sure it is power amp and not the preamp (for instance volume control).  Once you are sure (by switching channels), that problem lies in the power amp, then problem is likely bad connection somewhere.  Intermittent problems are very hard to troubleshoot and at one point you may need schematics and some basic test equipment.

@kijanki  that's what I was thinking. I know the issue is located in the amp. When I disconnect it from the receiver and connect the speakers to the receiver I have no channel issues. I'm going to check connections first, give it a thorough cleaning and test again before I decide to recap. My first stop will be the speaker cable connections and work inward from there. Thanks!

Check the relay contacts, or just simply replace the relay since it is more than 30 years old.

Dirty relay contacts is a common problem in vintage gears.

@imhififan +1

If it is that old relays should be replaced anyway to avoid future problems.  It might be as simple as that.

@imhififan thanks for the tip. I'll add that to my inspection list. 

I have a Pioneer SX-750 receiver that I bought new in 1977. A few years ago, I decided that it needed some work done on it, and I’ve had almost zero satisfaction taking it to a shop over the years. I went online to AudioKarma, then the Pioneer subforum, and a couple of great guys there walked me through the repair/renovation. It still cost several hundred dollars for tools and parts, and was slow as hell, between me educating myself on some stuff, coupled with posting a question and waiting for a reply. Still was pretty enjoyable.

@builder3 I've had hit-or-miss results with service shops in past and that were with the shop also being a dealer of the Marantz integrated amp I had years ago. I figured this old Adcom amp would make a good DIY project and an opportunity to sharpen my skills.  

I have recapped 5 amps- I left them unplugged for weeks on end; made sure the caps were fully drained; and replaced with higher quality caps of the same micro-farad value from Digikey. I am handy but not electronically trained. It wasn't that hard. You need a solder sucker. I suggest the electronic one if you are going to do this regularly. I also suggest a decent quality soldering unit.You can find lots of help online from various sources- especially on a  common amp like the Adcom. Good Luck.

@ovinewar1 Thanks for the tip on the solder sucker. I'll check out Digikey. I've had the amp disconnected and unplugged for about a month now. So I'm going to plan on doing my amp refresh over the New Year weekend. 

I see mention of relays causing output issues.  I bought an old Uni-Sync Model 50 recently, and I do hear the relays activate.  However, the right channel stays in Protect mode, while the left side begins in Protect mode, but gradually begins to go.back and forth between Protect and Ready until finally staying in Ready mode.  This is while nothing is hooked up to.the outputs if it matters.

I was planning on replacing parts in it as even the capacitors have signed stickers attached to them from the production process labeled '78, when it was produced.  I noticed the relays are not easy to find new, and they're not cheap like passives.

Thoughts?