[ScottSwan]

I'm trying to fix a Toshiba cx35d70 made in Nov '94 that has an odd audio distortion problem that I can't seem to figure out the cause of.

The audio sounds muffled and gets loud and soft until it warms up, then it stays at about 1/2 the volume it should be when turned all the way up.

I've replaced the audio amp IC and a few caps near it that reacted to a solder iron on top of them. I ran a heat gun all over the board and the audio seemed to get a little better but still garbled and it didn't "snap" into better quality in a specific area as I was hoping for.

I'm thinking it might be leaky something in the low voltage power supply but it still might be a bad cap. I don't have a schematic, so I'm at a loss for checking voltages.

Any suggestions, tips, specific caps or semiconductors to check would be a great help!

-Scott

[kiwiguy]

Instead of heating the components, try a can of "freeze it".

Rapid freezing will often identify the faulty component faster than heating will.

[ScottSwan]

I forgot to add that I did that, before I started on the heat actually. But I concentrated on the audio stuff, not the low voltage power stuff...
...I'll hit that tomorrow.

Thanks for the tip!

-Scott

[ScottSwan]

Well I froze every transistor and IC that might be even remotely related to this problem with no results.

The first thing that came to mind when I started working on this set is IF gain adjustment as it acts like the tuner is just a little off-key with the audio part. But I don't think this set has an adjustment for that.

It's not a tuner problem because this set has PIP and two separate antenna inputs, i.e. two tuners and I tried them both.

I think a schematic is needed at this point. Anyone know how I might get my hands on one?
I haven't been in the TV service industry for about 15 years now, so I'm not sure where to begin finding a schematic...

-Scott

[Zeppfan]

This sounds like a problem I had with an Akai Shelf stereo.

The problem I had was a crack in the volume controll circuit board. Slight seperation or crack in the board itself. I didn't have a pencil type soldering gun at the time.

I didn't bother replacing the circuit board because of the low cost of replacing the stereo.

This may not be your dillema, but I had to add my two cents.

[jhayaa]

TOSHIBA TV DISTORTED AUDIO: Did Scott or anyone find a solution to Scott Swan's "distorted audio" problem? Turns out I have a similar TV (Toshiba model CX35D60, manufactured in late 1994 also) with the same problem -- distorted sound that gets only slightly better after the TV has been on for 10-15 minutes. Like Scott's TV, mine has PIP and 2 tuners. The distorted audio problem is common to both tuners and all channels, even while picture is clean/clear. I suspect something in the built-in Surround Sound amp, or maybe a voltage problem somewhere. Audio is a little better when Surround circuit is switched off, but still poor. Audio is fully garbled when TV is first turned on, then gets better during 10-15 minutes afterward. Audio is then discernible, but poor. Volume has to be turned up more than half to hear it from across a small room. (1) Has anyone confronted and solved this problem? (2) Can anyone contact Scott Swan to find out if he found a solution? (My membership does not permit me to send him a message.)

[wacor]

he did not list an email and has not posted but in this thread with the last one being a year ago.

so your best bet is to start a new thread and explain in it your problem in detail along with what if anything you have tried.

[ScottSwan]

It's been awhile but I still get the email replies from this place.

The answer of if I ever solved that audio problem is a sad no. I spent a lot of time replacing caps and trying to track down the source of the problem and I never got anywhere with it. I finally told the owner to use the audio output (RCA) jacks and run it through a stereo amp. I'm assuming that works fine because I never heard from him again after that.

[jhayaa]

Thanks for the replies. In the week since I last posted, the sound amp has started to intermittently shut off altogether. Before, the sound got better after the TV turned on for a while. Now, after it's been on for a few minutes with distorted sound, it produces no sound at all except in spurts of about 20 seconds every few minutes. I haven't tried using an amp off the RCA Out jacks, but that was going to be my next step. If anyone knows how to replace the sound amplifier in this Toshiba CX35D60 TV, please let me know. Thanks.

[ScottSwan]

Intermittent is a good thing! You should be able to find the problem using a few tricks.
1) Tap around on the board near the audio with the butt end of a screwdriver, see if anything changes.
2) Freeze spray the audio amp chip and any related IC's or transistors. The sound will probably SNAP back to normal if you hit the right one.
3) Use a heat gun... but that is hard to focus. I use a soldering iron on top of the electrolytic caps and if the cap is bad it will temporarily fix it.

Mine was never intermittent, which made it really hard to nail down. So hard that never nailed it down in fact!