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Can i have some help for yakin VK-2100
- Thread starter Etienne56
- Start date
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Can you post a schematic using the "Upload a File" button? Maybe circle the resistor that's burning up.
Jack
Jack
analogadict
Active Member
Does it can à bad bias? I am in france and we have 240v and this yaqin is made for 220v is it a problem?
Perharps i go to far away in in my "up grade"
The accident come after a new rolling tube and i decide to change the 220v fuse by another (better) when i turn on many piece and fuse died
Perharps i go to far away in in my "up grade"
The accident come after a new rolling tube and i decide to change the 220v fuse by another (better) when i turn on many piece and fuse died
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The first thing you should do is to test all the transistors in the power amplifier for shorts and opens. You can do that with an ohmmeter. You'll probably need to remove the 200Ω resistor to test everything in-circuit, because it bridges the bases of the outputs and the emitters of the driver transistors.
Jack
Jack
Although this is a hybrid amp it seems the issue might be in the solid state power amp section. In that case, would you prefer this thread be moved to the Solid State forum for troubleshooting help in this section?
Thanks lets go!
I don't know which leads you're testing or how that tester works. You will need to remove some of the transistors or disconnect one or more leads for ohmmeter tests. For example, the C-E junction of Q6 is in parallel with the C-B junction of Q7. In a case where you know something is wrong, but there aren't any shorts, removing all the devices is the best way to test them. Also, be sure to test C6, C7, C8 and C9 for leakage. I might be tempted to remove them and leave them out until the power amplifier is repaired. If all this looks good, you need to check resistors and pots before attempting to apply power again.
When you first apply power after finding a defective component, be sure the speakers aren't connected. Use a Variac to check for excessive mains current draw and to avoid damage if something is still amiss. It's also a good idea to monitor the voltages across each emitter resistor (R31 & R32) while increasing the mains input voltage with the Variac. I would expect about 10mV or 20mV maximum if this is AB1. Once the amplifier is up and running, check the output at each channel for offset voltage before connecting speakers.
Jack
When you first apply power after finding a defective component, be sure the speakers aren't connected. Use a Variac to check for excessive mains current draw and to avoid damage if something is still amiss. It's also a good idea to monitor the voltages across each emitter resistor (R31 & R32) while increasing the mains input voltage with the Variac. I would expect about 10mV or 20mV maximum if this is AB1. Once the amplifier is up and running, check the output at each channel for offset voltage before connecting speakers.
Jack
No, use an incandescent (filament) light bulb. Probably a 40W or 60W will work well for test.
Jack
Jack
