Reply with quote #1
I acquired a T16 stereo amp from a friend of mine this week. I built a grounded grid preamp many years ago that I still use, so I was excited to try this out. They told me they had a problem with one of the four 1/2amp fuses blowing, but I changed out the tubes and solved that problem. That was also on the channel that is currently working. I switched the driver tubes from left to right, and that didn't change anything, so I assume this means the problem is in the circuit somewhere. Input impedance is the same on each channel, and I know that at one time both channels worked for this person, so I am wondering how to approach this from here. I do have a manual I have been going over, and I saw in the Articles section about the update with the bad tube problem (that update had been performed on the unit), so basically I need some direction.
Reply with quote #2
Complete silence is strange. Are the filaments glowing? Even without anode voltage usually some input signal is heard through speakers (not sure about this specific amp). It seems the signal is shorted to ground somewhere around the input tubes. First check all possible DC voltages, you can compare with working channel.
Reply with quote #3
Yes, the filaments are glowing in all the tubes. The signal isn't shorted to ground, there is a 99.6Kohm resistance there. I will check all the DC voltages though to see if that points to something. Thanks!
Reply with quote #4
I measured all the DC points I thought I could find on the driver boards and everything measured okay except for the OUT + and -. The working channel measured 347 and 348 respectively, while the other channel measured 190 on the + and 210 on the -. Is this a tube issue, or which circuit components should I be looking at?