• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

Balanced Audio Technology VK-D5SE

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#103
jimmyp11 said:
Here goes. Left channel filament heats up fine, right channel filament seems to cycle for some reason. Each filament channel has its own voltage regulator, which is variable. They use the variable to ramp up to 6v. I did replace both, same issue. There is a relay on a separate circuit for the plate voltage. When this engages the plate voltage, it causes the right channel filament voltage to cycle, but not the left.

In standby mode, the player just heats the filament. In this case, both channels rise to 6v. But hit power to come off stand by and the above occurs. Now other issue is plate voltage on working channel is 150v. Plate on right channel is 130v, and the plate resistors are heating up on that channel. Not sure if this is a cause of that filament not being at 6v when the plate voltage kicks in? When the filament is cycling, it takes a long time to get back to 6v. In the meantime, the plate voltage kicks in.

I can upload schematics in the am. But that's the issue. I have replaced all electrolytic caps, both filament voltage regulators, and said relay. No help, same issues.

jim
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There is definitely some current being pulled since the plate voltage is reading 130vdc and the plate resistors heating up for that channel. I know relays can do funny things and cause weird issues. Maybe pulling the one on the bad channel and checking it out of circuit if it's working properly, Open/Closed.
 
#108
jimmyp11 said:
I already replaced those. They were cheap at mouser. They have been replaced 90% of the caps, bunch of transistors. Too many issues, you fix one and another pops up. I'm officially calling it. Thanks again for all the help!

jim
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Was this before the issue or after you had the issue/s? Just so much time and work for someone else to find the fix since alot has been done already and have a nice CD player but I understand your frustration.

Sometimes its good to just go after the first/main issues cause if you recap before you fix the main issue, you don't know if the other changes may have caused more problems. I learned that the hard way back when I was younger. I had this happen to me on some Recapping/Upgrades on some units that were not working and then it became a mess. Always good to get the unit/s working before changing anything else, once working then you can change caps or resistors one at a time to make sure if anything goes wrong, you know which change cause it.

Steve
 
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#110
It was a pleasure, thanks for trusting me on the changes to the device. If I may give a last word of advice: check your soldering iron for good anti ESD measures. As I wrote, mine is good since I check the tip is grounded, yours may be different. A bad soldering iron can go zapping all SS components it finds through its way.
 
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