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Thanks again for all the help, Mark. Your suggestions were all well thought out and sent me in directions that I likely would not have thought of. A great learning experience! All resistors tested within 1 ohm of expected values except one of the 300 ohms. It was around 290, so I replaced it...

Short circuit issue has been resolved. Turns out a mica insulator on an output transistor was cracked with a small piece missing. Q21 and 22 are original. Diodes seem to test fine - about 1.5v drop for the STV-3h and .6v for the 1s2473, although I can’t be sure that’s the original. They look the...

Jumpers are intact. According to service manual, cutting them should increase bias so that's not an option. Outputs are original bat-wing transistors. Drivers had been updated at some point to KSA1013 and KSC2383 which I think should have been ok, but I still replaced them with some original...

Further testing with dim bulb shows 70mv bias on each channel instead of suggested 10. With full AC applied, bias jumps to 120mv each channel… Obviously something is not quite right.

Thanks for your help, Mark! I agree the protection design is a little brutal. I had removed the triac previous to your suggestion of disabling the protection circuit with no change to the symptoms. I also removed the 1 ohm resistor after your suggestion. The problem of having stable operation...

Hi All! I’ve been working on the amp for the past few days after picking it up as a repair unit. The power switch was broken and I don’t currently have a replacement, so I have temporarily jumpered across it to get it powered up. Initially there was an issue with the signal being distorted on...

Thanks for your input, Okke 70s! I had re-flowed the solder joints related to the IF area, but that had not solved the issue. So, I did replace the chip with the recently purchased one. Good news and bad news. The bad news is that the issue of usually no audio at the output of the chip remains...

Hi Everyone. Hope your holiday plans are coming together nicely. I've got an issue with no sound on FM, almost all of the time. Sometimes, for a few seconds (max about 10), it works. Good audio, stereo light, meter movement. But then, it stops completely. No audio, no meter deflection, no stereo...

I may try to do something similar with my unit at some point. In the amp’s previous life, likely because of the original dual tap volume pot breaking, someone made some alterations to the wiring of the attenuator switches. That further complicates the situation. Right now, I’ve bypassed the...

Thanks again for your help. Success getting the power supply board recapped. Pictures show the angle I managed to get the board positioned at providing enough room to remove and install components, and completed recap. Wasn't brave enough to desolder all the pins....

Good advice from Mark and very useful photos from the Netherlands! I'll try to get back at it tonight and see how it goes. If all goes well, next step will be to try and come up with a way to replace the original double tap volume potentiometer and reconnect the attenuator and loudness components.

That would be great if you have any tips on removal! Here are some photos of the installed board:

Found two transistors ((2sc1313) on the Filter Amp board (AWK-020) with their tops blown off. Replaced them, checked all nearby resistors and replaced the electrolytics on the board and all seems to be well as far as the power supply and audio signal problems. Still trying to figure out a...

Thanks for your comment, Mark. I've learned a lot from you over the past few years and I'm sure will learn more in the future. Your experience and suggestions are much appreciated. I will be looking into the cause of the low load on pin 17. There is an issue somewhere (likely on the boards...

Thanks, Keith. I've gone straight into the Power Amp inputs on the back and get a clean signal to the speakers, so at this point, I know that section and the protect section including the relay are working ok right now.. I will take a closer look at the relay when I figure out some issues in the...

Hi. I recently picked up an SA-8100 listed as 'for parts'. It was pretty dirty and missing its volume pot, but looked like it deserved a second life. So, I've started the restoration process. I replaced the volume pot with a standard dual linear taper with loudness tap for the time being, since...

Here's an update and I'm hoping some of you tuner experts might have some advice. I've attached a photo and partial schematic to help explain the issue. The photo shows the tuning and signal meters when the FM tuner is selected. The only audio coming out at this point is white noise, all across...

Thanks for the response, Punker X. I wish it were that simple. I used 1mv or less into the anntenna terminals. The same thing happens with a strong local station - appears multiple locations across the tuning dial, but mostly above its actual frequency. Weak to moderate stations can't be heard...

I've been working on restoring a beautiful STA-960 receiver for the past while and have managed to get everything working on it (it was a parts/repair unit) except the FM tuner. While all the tuner functions work (stereo light, muting, meters), there remains a major problem with the tuning...

I didn't initially notice the hum because my bench speakers are Realistic Minimus 7s. They're great for their size, but they don't reproduce very low frequencies well. When I attached full size speakers, the hum was noticeable and I could see about a 50millivolt 60 cycle signal on receiver's...

So it turns out to be a design issue. After moving the two green caps (part of the loudness circuit) as far as possible from the power switch/capacitor combo, the hum is almost completely gone.

Thanks for your suggestions, Lavane. I have double-checked the solder joints on the tone board and they all look good. While doing that, I did notice a design choice that seemed odd. In the photo below, it can be seen that the main power switch, and capacitor across it, are right next to the...

Thanks to djwhy60 for the manuals - extremely helpful! I'm just finishing up a restoration and having the documentation meant everything went much faster and easier. It is working almost perfectly and sounds great. However, there is a small hum issue that seems a little unusual to me. I think...

Still no luck getting anything resembling the curves in the alignment instructions, but I'll keep plugging away! I'll take some time over the weekend to read through the information in the Sencore SG-165 manual to learn more about alignments in general. I'm finding a lot of new (to me)...

Thanks, again. I'll try out the settings you suggested tonight and see what happens. I've also downloaded the Sencore manual. Looks like a lot of good general information on the topic.