SX-3500 repair and restoration

[nicholas2381]

Shoot on sight transistors replaced. Working on an order for a few replacement bulbs.

 

[nicholas2381]

Getting closer on this one. Got my replacement bulbs in. Even after replacing the speaker B LED it still doesn’t light, so that’s likely up the chain, possibly at the replacement switch.

Investigation to come.

 

[nicholas2381]

OK, got the speaker B light working. Had to bridge a broken contact. No big deal.

But there is a volume imbalance b/t right and left channels.

1khz test tone. 1.5 on the volume dial.

Left channel sine wave: 3 peak to peak
Right channel sine wave: 2 peak to peak.

Gotta sort out where I’m losing my amplitude in the right channel.

 

[nicholas2381]

Interesting find: when I disengage the speaker switch the on-unit Watt meter shows the volume normalizes between channels.

Same for both speaker A and B, but only when a load is connected.

 

[nicholas2381]

It was a problem with the connection running through the tape monitor switch. Now resolved.

 

[nicholas2381]

Unit is buttoned back up and in use as my office system. I'm holding off on the recap for the time being since it sounds good and everything seems to be working. Saves me some funds for now to apply to other projects under way and upcoming. I still might recap it down the road.

Fun little receiver!

 

[Way San]

Shoot on sight transistors replaced. Working on an order for a few replacement bulbs.

I'm working on an SX-3900 that needs function indicator bulbs. 8V 50mw. Mini bulbs with attached leads. Are the bulbs you replaced similar? Where did you get them? Or did you sub them with LEDs?

 

[nicholas2381]

I'm working on an SX-3900 that needs function indicator bulbs. 8V 50mw. Mini bulbs with attached leads. Are the bulbs you replaced similar? Where did you get them? Or did you sub them with LEDs?

Fellow AKer @dgwojo can help you out. I order my bulbs from him at: https://sites.google.com/site/dgwojocom/

The only indicator bulb I needed was for speaker B and it was an LED.

 

[Tom Benner]

Back to Pioneer for this project. I present to you a mostly-functioning, decent cosmetic Pioneer SX-3500 from my project pile:

View attachment 2215612

Primary issues on first inspection:

Switches for speaker A, speaker B, tape monitor and loudness won’t stay engaged.

Slight volume imbalance (left channel slightly louder than the right).

Positive speaker terminal for left speaker of A has lost its springiness.

Needs a good cleaning, but otherwise in decent shape. No obvious burned or exploded components.

View attachment 2215618

Nice, I've a sx-3500, is similar, complete with brittle plstc pieces, bad springs for push buttons. I replaced my speaker terminals. Easy to work on. In my basement, sounds good. Let me know if you need parts..