SA250/SC25 Sonographe Problems

[SamVimes]

I know these are ancient pieces but they are MY ancient pieces and I want them to work properly again.

Many years ago my toddler grabbed the volume knob and there was an event. It was not a good one and it also damaged my Thiels.

Life intervened, I boxed them up and they sat for a long time. A very long time. CD player is my only input, let's assume everything is connected properly.

Here are the issues:

- The balance knob does not move the sound left to right. Turning the knob entirely in one direction or another has no apparent impact on sound.

- The mute button creates an audible hiss that disappears entirely when I push the CD button.

There is stereo separation. I opened up both units to check fuses and otherwise eyeball for obvious problems. All fuses are fine and nothing obvious to see - nothing burned, melted, scorched, loose that I can tell.

Is there anything obvious from my description or is the only answer to just send it in for service? I don't have additional equipment to examine the amp separately but I don't think the issue is there. The nice people at CJ basically said send them back for diagnostic service, but warned me in so many words that the likely cost of any repair + shipping was probably more $$ than these were worth. This was hard to hear but the candor was appreciated.

Any ideas? Suggestions?

[admin]

First, welcome to CJO. Nice to have you with us.

So this is a rather old unit so one would expect some problems after all these decades. As for things to try:

1) Are you sure there is no subtle change in volume. I have a PV12 and each click of the balance selector is only 0.75 db attenuation. In other words, even with the balance knob all the way to the right or left, the volume amplitude change will be minor (just a few db). This is the same for the SC25. Have you used test tones and an external sound volume meter to confirm that there is no change in amplitude when the selector is used? This may be simply out of your discernable audio perception,... especially if you are playing music and not test tones.

2) This could be a bad contact amongst other things. Maybe some contact spray on the button to see if it can be cleaned up? Of course this can also be an internal component failure. I would check for the obvious signs,... burn marks, bulging caps, etc...

You can of course call CJ and see what they can do with it but it's going to cost some money (perhaps even more than what the unit is worth on the used market).

[AnotherJohnson]

Yes, admin and CJ are both right. Not worth the cost to fix... unless there is some nostalgic reason to fix it.

[SamVimes]

Dear Nice People:

Update, now almost four months later. The cd player stopped working so I got a Bluesound Node 2i, and after some contact spray the preamp knobs seem to be working just fine. Related, the very good people at Coherent Source Service sent me a new woofer to repair the Thiels and we are back in business! Still get the buzz from the mute button but I'm not sure what the purpose of it is anyway. I now think Admin was correct in the subtlety of the balance knob, supported by my kids whose hearing is far better than mine. Many hours of happy listening!

[admin]

Glad to hear the system is up and running. Sorry to hear the CD player stopped but you can always put it on the bench and see if you can repair it. I find that I am a little bit more "bold" in my repair approach when I have a replacement already in the system. You never know...