Airline 62-9015-A

[angelodp]

I do see a voltage rise, AC, on one side but not the other?

Caps are coming via amazon to address the Trem.

[angelodp]

Ran a resistance check on all grounds and they are good.

[angelodp]

Just hooked this up to an 8 ohm 2x12 cab and I beginning to warm up to this amp. As expected the bigger cab is allowing for more dynamics and punch.

Hope the new caps fix the tremolo issue. Not sure how to proceed with the Reverb, short of going with a one tube design. I just got a few tanks from a pal.

[angelodp]

R38 and R39 were both toast, no plate voltage, now replaced.... still no reverb.....

Should I expect roughly the same voltage on pin 6 as pin 1?

[angelodp]

Reverb awake now, but not full strength. Its there alright. I am gonna change out various caps and R's. Maybe a full refresh is in order. Its starting to sound like an amp with some merit.

Need to order some caps, stash is low.

[angelodp]

Working on the Trem. I lowered the 1M to 470k R41, R44 was toast so put a new 330K, but still have no voltage at the screen grid g2? I do have voltage on the other side of the 330k but it is being dropped
completely on the other side? Does this appear to be an on all the time setup at the footswitch? I have plate voltage about 240v. Will channel A or B work for Reverb and Tremolo? I also increased the Plate resistor to 220k. I am following a thread on Hoffman physconoodler, got his going with some of these prescriptions.

[sluckey]

Most likely suspect is C23 shorted.

[angelodp]

Had already replaced that non-polarized wax cap with a .68uf as I did not have a .5 on hand... might that create any problems.

I get no voltage on pin 6 where it says 90v avg. I have changed out almost all the caps now and checked the R's?? Not able to jump start this LFO? Any suggestions.

[sluckey]

Measure resistance between pin 6 and chassis. What have you?

[angelodp]

20 ohms - I think I have some mis-wiring by previous owner on the two Tremolo pots, sorting out now.

[angelodp]

sluckey, with 20ohms as I have what does that tell me? How can I proceed with the trem fix?

Here is a layout of the trem section. I think its in in order, but I question how the Strength and Speed pots are wired.

[sluckey]

Pin 6 should measure 330KΩ to chassis but you are only measuring 20Ω. That's why you have no voltage on pin 6. C23 being shorted is the first suspect. Just disconnect the cap and see if you now get the proper resistance reading.

The next suspect is a component touching something it should not touch or a wiring error. Should be easy to sort with just your ohm meter.

[angelodp]

Egads, I put in a .68uf 160 cap.... dumb move. Its toast and yes you are quite right. Looking for the correct cap. I reckon that 320v did that cap in.

back when I am up and running


Thanks Steve.

[angelodp]

Ok I put in a 600v .5 cap non-polarized, like what was in there originally (wax type was in there). That was not a good thing. I think the onrush of current did in the other .022 coupling caps especially the ones leading into the 6L6 tubes. Amp now does not conduct except a sputter at high volumes. I have a bunch of .022's coming in.

Should I be using a polarized cap in place of the the .5uf cap C23?

I ran through the entire startup per Rob Rob and Sluckey -

Heaters check out, AC correct, w/just the rectifier all DC & AC voltages appear to be correct. Caps charge and are at high DC
I am using a bulb limiter and when I load the tubes it has a low glow.

[sluckey]

Pin 6 should measure 330KΩ to chassis but you are only measuring 20Ω. That's why you have no voltage on pin 6. C23 being shorted is the first suspect. Just disconnect the cap and see if you now get the proper resistance reading.

You never said what the resistance was with the cap disconnected.