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I'm participating in a few groups on FB that touch new and vintage Hi-Fi. Should not only be totally do-able, but the results should make the work really worthwhile. I need to at least learn how to clean pots and do some trivial resoldering.
I think capacitors die with age. 30 year old receivers often have capacitor kits available for them. Lots of fine de-solderig and re-soldering. The big ones on your speakers are dirt simple to refresh.
I love old amps! I have a Dynaco SCA-80Q that I built from a kit in 1973. Except for replacing an electrolytic cap that was causing hum a couple months ago, it still works perfectly. In fact, I have it hooked up to play audio from my PC. Not my pic, but this is it:
Again, not my pic, but the electrolytic cap in the middle left is the one that went bad. No direct replacements available, but I found a work-around on E-Bay.
Edit: I think my wiring job is neater than that^.
2nd Edit: Dynaco made some great electronics.
I love old amps! I have a Dynaco SCA-80Q that I built from a kit in 1973. Except for replacing an electrolytic cap that was causing hum a couple months ago, it still works perfectly. In fact, I have it hooked up to play audio from my PC. Not my pic, but this is it:
Again, not my pic, but the electrolytic cap in the middle left is the one that went bad. No direct replacements available, but I found a work-around on E-Bay.
Edit: I think my wiring job is neater than that^.
2nd Edit: Dynaco made some great electronics.
Very cool resto!
Unfortunately, no "Cap Kits" for specific NAD amp models. Actually, no kits for most solid-state units. Still having problems finding 120VDC rated, 10,000 mfd 'lytic filter caps. Nichicon stopped making these around mid-2000s.
Also, having problems finding power relays for the output stages. Of all things, it seems a 24VDC auto relay works. I bought last two off Amazon.
Here is the issue with the power filter caps. They barely fit under the top cover. And are soldered right into the main board. So, the dimensions as well as the ratings are critical. Of all things, the first stage main caps (120VDC rated) are the ones that are bulging on the top.
Top view:
Bottom view:
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Good news is I took all my JBL speakers and crossovers to be checked and fixed by Speaker Repair Pro, in Garden Grove (OC), CA.
Very nice man. Young, too (I'd say in his 30s). He tested all my midrange and high frequency speakers on a signal generator and scope.
All were well-matched, except the midrange in the L-100s. Slight impedance mismatch between the two LE-5 speakers. One being little over 9-ohms.
He will recone all my 15-inch 136A. When he tested the 12-inch 123A woofers, he found one had a slight rub in mid travel. He will remove the cap and pull back on the voice coil to try and find the problem.
Also, will recharge the alnico magnets on the six woofers.
Spent a good hour talking speakers, fixing audio, and guitar amp gear. So far, so good...
Good luck finding the caps. I'm sure they or work-arounds are lurking somewhere. BTW, the pictures I posted are not of my amp, but ones I found on Google Images.
Man! It is so hard finding correct, specific parts for many solid-state products. Much easier finding correct parts for 50-60+ year old tube amplifiers.
Think I'm gonna get some modern amps, in the meantime. While searching for correct parts (at reasonable cost) --- for the vintage NAD amp. That way I can hear tunes, when the speakers come back.
I have had some specialty outfits work on my Yamaha Natural Sound M70 200W amp and C70 control pre-amp as well as my Marantz 2230 receiver (original caps are hanging in there!) I found one guy in Florida who does good work with turntables but I have not shipped it yet. It is a tangental tracking Pioneer PL L800. I have an older regular Pioneer that is still making my vinyl spin.
My mid 1980 Bose 901s were shot. Bose took them back and shipped me brand new 901s with equalizer and free stands (Thanked me for my Navy service-they could tell by the serial numbers I purchased the originals overseas at a military base!)
10-29-2017, 10:00 PM
Restoring vintage audio system.
