Traynor TS-200 - Capacitor Question

[dtsew]

The saga continues...

I don't know if the problems are being solved or I am making mistaken diagnosis?

After installing the new Master Volume pot it seemed to work, sort of. Owner playing the guitar and then it cut out. Thump on the unit and it comes back. Turn the volume low and it seemed to have a signal out. Turn the volume too high and the signal cuts out.

Chased this around and around. Finally found that the signbal disappears at the Treble potentiometer which is ahead of the Master Volume in the schematic before finally sending the signal to the power amp.

I have a plan. To remove the Treble pot is a fair bit of work and I don't know for sure if replacement is the guaranteed solution. Based on past experiences, the problem will simply pack it's bags and move down stream to another component. Nonetheless, becuase removal requires desoldering ALL the potentiometers (been down that road once already to replace all the electrolytic caps) and the knob doesn't come off without a fair bit of work and patience (which ultimately destroys the potentiometer) I have decided to temporarily solder 22Kohm resistors from each outer lug to the wiper. I will set the knob to middle range and test if the signal passes through.

 

[dtsew]

Update - 22Kohm resistor values too high. Using one small resistor on side with 680pF capacitor connected. News at 11.

 

[Northwinds]

I have a 1970 YSR-1 Custom Reverb all tube stack. I guess I am very lucky it still has zero issues. Traynor, at least in the tube head days was some of the best affordable amps, all point to point wuring with robust trannies. They competed with Marshall and Fender for years. Unfortunately I know nothing about any of their SS amps but wish you luck with this repair

 

[Mr Boochie]

The saga continues...

I don't know if the problems are being solved or I am making mistaken diagnosis?

After installing the new Master Volume pot it seemed to work, sort of. Owner playing the guitar and then it cut out. Thump on the unit and it comes back. Turn the volume low and it seemed to have a signal out. Turn the volume too high and the signal cuts out.

Chased this around and around. Finally found that the signbal disappears at the Treble potentiometer which is ahead of the Master Volume in the schematic before finally sending the signal to the power amp.

I have a plan. To remove the Treble pot is a fair bit of work and I don't know for sure if replacement is the guaranteed solution. Based on past experiences, the problem will simply pack it's bags and move down stream to another component. Nonetheless, becuase removal requires desoldering ALL the potentiometers (been down that road once already to replace all the electrolytic caps) and the knob doesn't come off without a fair bit of work and patience (which ultimately destroys the potentiometer) I have decided to temporarily solder 22Kohm resistors from each outer lug to the wiper. I will set the knob to middle range and test if the signal passes through.

Also, watch those little disc caps around tone stacks and hanging off pots! They can crack, or the solder can get cold, and the amp will do all kinds of oddball things, that will drive you crazy.

Tapping them with a wooden chopstick (or non-conductive probe) often narrows down the specific solder point or cap. But, you know, if one cap is funky, I replace all the disc caps and resolder everything.

I don't know how many people have replaced pots, only to have the same problem pop up two weeks later. Circuit board tracings, solder points, and disc caps.

Good luck!

 

[dtsew]

Update

What I found during another troubleshooting session, where the signal was missing at the Treble pot, is that when I pushed on one of the new electrolytic capacitors the signal returned. When checking with a meter set to resistance there was no signs of a bad joint. I understand that isn't the same as a power ON test so I remade the solder connections insuring the leads were pressing against the trace. I did this earlier with other components on this board where it looked like the component lead is not physically touching the board to insure a good connection. In those prior situations that was done out of desperation rather than believing or knowing it made a difference.

Again, powered the amp on and played for several minutes. Tried tapping on the panel to get the signal to cut out. Never flinched. Stayed solid.

Maybe this is common knowledge when soldering component leads in circuit boards where the openings are significantly larger? Never really thought about it until now because it hasn't come up. Here's my terrible "egg in a frying pan" illustration of what I am talking about:



The last image poorly illustrates how I noticed most of the other smaller components were soldered to this board. I will follow suit from now on. So far the amp is working fine.

 

[Mr Boochie]

Cool!

I hate some of these older circuit board amps. The solder they used and the quality of the soldering work were not great.

I have had to resolder every tracing, every component on the board, EVERYTHING, on some amps to make them reliable.

There are amps that I will no longer work on. Like 1990s-era Peaveys.

 

[dtsew]

@Mr Boochie

I am just getting into more audio equipment repair and never realized how common an issue the soldering connections can be. I am assume it has to do with it being audio and therefore the resulting vibrations that reveals any less than ideal solder connections?

 

[Mr Boochie]

@Mr Boochie

I am just getting into more audio equipment repair and never realized how common an issue the soldering connections can be. I am assume it has to do with it being audio and therefore the resulting vibrations that reveals any less than ideal solder connections?

Also, oxidation and long-term temperature changes damage the solder. It makes it brittle and prone to cracking. A lot depends on the quality of the original solder (which is often unknown) and the soldering job.

And the darn cracks can be very small, so they're not easy to see without a magnifying glass.

If I have doubts about the age or quality of the solder, I remove the old stuff and lay down some new, quality solder. I like Kester 44.

I aim for small, shiny, smooth solder points. Those seem to last the longest.

 

[dtsew]

I can't find a user manual for the Traynor TS-200. What I do know is that the unit I have been working on comes with the TS-98 speaker cabinet. The two were sold together.

Traynor TS-200 rated for 200 watts with an internal 8ohm 10W speaker.

TS-98 has 9x 8 ohm speakers with a total of 150 watts.

Any idea what the purpose of having an output such as "INTERNAL SPK ON" would be used for? Obviously you wouldn't want to connect the TS-98 speaker cabinet through that output.



Interesting that the electrical schematic uses different terminology for these "outputs". The diagram refers to the 2 as "Internal Speaker In" and "Internal Speaker Out". Internal Speaker Out according to the diagram has the normally closed contact which when a jack is inserted would disconnect the internal speaker. Therefore, Internal Speaker Out is INTERNAL SPEAKER OFF (this has been tested to be true).

Thank-you

Edit: on the positive of the "output jacks" there is two 125ohm 5W resistors in parallel connected to a 47uF 75V bipolar capacitor which then connects to one side of the internal speaker (other side connects to ground). This should allow the internal speaker to be connected in parallel with the speaker cabinet without harming it?

 

[Mr Boochie]

I think the "Internal Speaker On" leaves both the internal and external speakers active. If you are running the external speaker far from the combo amp, you could get a slightly funky, delayed sound for the guitarist with both INT and EXT speakers on. This can be a little annoying while playing.

But if the EXT speaker is close to the combo amp. Then you get real-time sound reinforcement.