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Weal channel at power-up in both Claricon 36-350 and Sansui R-5

UncleFutz

UncleFutz

New Member
I have two old receivers with the same issue - when first powered on, one channel is very weak until I crank the volume to a certain point, then it kicks in loud and clear. From this point on, all volume settings up and down are perfectly balanced. Any idea what might be causing this?

If it matters, one is a Claricon 36-350, and the other is a Sansui R-5.
 
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get schematics and try adjusting the bias. could be anything. have they been serviced recently and how about some internal pics?

Claricon 36-350 Receiver - info wanted

I picked up one of these of off Craigslist the other day for a mere $25. I know it's not a McIntosh or even remotely similar, but there is VERY little information on the internets about the receiver or the company, Claricon. It looks like they made a lot of walkie talkies and CB radios back in...
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Sansui R-5 Volume drops at high output power

Customer of Repair Cafe asked for new life to be put into his beloved Sansui R-5 that he claimed had lost one channel. No fault found when I ran it, but I suggested we recap it if he wanted to have it around for awhile. After recapping, tonight I test ran it at near full output. After about 5...
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Here is schematic and pics for Claricon. Just finished re-capping power, pre-amp and output circuits. Problem didn’t show up until I had put unit back in walnut housing. Maybe I bumped something, but thought it was odd that just turning up the volume past a certain point “corrects” the issue on both units.

I haven’t been into the Sansui yet. It’s had the problem for a few years now, but I don’t use it much, and never gave it much thought until the Claricon started doing the same thing.

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Schematic hard to see but it looks like the headphone jack switches out the speakers when used. If so that is the first place I'd look. A bad connection there is a barrier that higher drive voltage might overcome and establish a connection, higher drive voltage when volume is turned up. Protection relays, not uncommon for them to have this problem although this set does not a relay, same sort of issue though. Try headphones, see if they are good, if related inserting plug might make it work, if so that is probably the issue.
 
spicer said:
Schematic hard to see but it looks like the headphone jack switches out the speakers when used. If so that is the first place I'd look. A bad connection there is a barrier that higher drive voltage might overcome and establish a connection, higher drive voltage when volume is turned up. Protection relays, not uncommon for them to have this problem although this set does not a relay, same sort of issue though. Try headphones, see if they are good, if related inserting plug might make it work, if so that is probably the issue.
Click to expand...
Thanks, Spicer. The headphone jack does indeed switch the speakers out, so I’ll look there first on both units. Will keep protection relay in mind as a possibility for the Sansui.
 
I managed to find a 1/4” to 1/8” adapter to listen more closely to the Claricon output, and it’s a bit different than I originally thought. When switched on via integral power/volume knob, there is very faint audio in the left channel; nothing in the right. As I slowly increase the volume, the right channel suddenly kicks in at the same volume as the left. Going back down, the right channel cuts out at the same point.

Whether it’s related or not, the left channel has a 120 hz buzz that is completely independent of input source or any controls - it’s just always (annoyingly) there, and has been since I got it. I’ve replaced the electrolytics in the power, preamp and output circuits, and checked every ground connection I can find. I would really appreciate any help on where else to look. Here’s what I hope is a better resolution schematic.


IMG_1573.png
 
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UncleFutz said:
I managed to find a 1/4” to 1/8” adapter to listen more closely to the Claricon output, and it’s a bit different than I originally thought. When switched on via integral power/volume knob, there is very faint audio in the left channel; nothing in the right. As I slowly increase the volume, the right channel suddenly kicks in at the same volume as the left. Going back down, the right channel cuts out at the same point.

Whether it’s related or not, the left channel has a 120 hz buzz that is completely independent of input source or any controls - it’s just always (annoyingly) there, and has been since I got it. I’ve replaced the electrolytics in the power, preamp and output circuits, and checked every ground connection I can find. I would really appreciate any help on where else to look. Here’s what I hope is a better resolution schematic.


View attachment 3298184
Click to expand...
Do you have a scope? A fault like this, would most likely pin point the problem when it exists. First thing I'd check is signal right after the output cap. From the description almost for sure after the volume control if not the control itself.
 
UncleFutz said:
Just curious - How would I go about it without a scope? Have DMM and cap/ind meter. Thanks.
Click to expand...
It's basically signal tracing using the DMM to display signal voltage set to ac low enough on the scale. Use any source, FM is fine, and check for equal signal levels at various points. Provide enough gain for DMM to easily display and compare signals channel to channel at various check points, see where the signal stops or greatly changes in level, you'll be at the area of the problem. The schematic is larger but still hard to stay focused, it's hard without a zoom in zoom out. (don't short anything out with a probe)
 
spicer said:
It's basically signal tracing using the DMM to display signal voltage set to ac low enough on the scale. Use any source, FM is fine, and check for equal signal levels at various points. Provide enough gain for DMM to easily display and compare signals channel to channel at various check points, see where the signal stops or greatly changes in level, you'll be at the area of the problem. The schematic is larger but still hard to stay focused, it's hard without a zoom in zoom out. (don't short anything out with a probe)
Click to expand...

spicer said:
give that a try
Click to expand...
Thanks. I’ll give that a try.
 
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