Traynor ycv40 low output

[J M Fahey]

Well, that is very weird, and hints at still unresolved problems.
Transformer tap voltages do not change on their own, and with 4V on filaments that amp would never have worked ... or worked so poorly that nobody would buy it.

That amp has all voltages regulated (even +V) , very unusual, and that may be hiding a very wrong transformer connection.

Only unregulated voltage there is power amp filaments.

I wouldn't worry much if I found, say, 5.9VAC or 6.9 , but 4V is gross.

I'd love to know DC voltages at:
C38 and C5
C55 , C19 , C41

And please reread filament voltages, straight from pin2 to pin 7 on power tubes and across (tabs?) WC5 , WC6 .

Something does not add up here.

[nosaj]

c38 33 VDC
c5 24vdc
c55 411vdc
c19 154 vdc
c41 425vdc
wc5/6 4vac
v4 pins 2,7 3vac
v4 pins 2,7 3 vac

Transformer leads disconnected read 4 vac.

short in the winding maybe? I know subbing in a 6.3 filament and amp sounds great.

Any other measurements let me know.

Thanks,
Jason

[52 Bill]

Did you check R95 and R96 on the heater circuit?

[nosaj]

Did you check R95 and R96 on the heater circuit?

I will but voltage straight off PT is 4 vac which is where problem starts. ohm'ed the 6.3 heaters and got 1.1 ohm.

jason

[g1]

Yes, if the heater winding is 4VAC disconnected, then it's pretty much bad.
What seemed odd was that you said you had only 3VAC at the power tube heaters. So is the voltage from WC5 to WC6 dropping to 3VAC when hooked up?

Also, I'm assuming it's not running right without the external heater supply?

[nosaj]

Tested good but then realized amp was not on Variac anymore. AC into amp was showing 115. Put back on variac for 120 and 6.2 vac heaters.

Thanks to all who helped it get here.

Jason

[J M Fahey]

voltage straight off PT is 4 vac

amp was not on Variac anymore. AC into amp was showing 115. Put back on variac for 120 and 6.2 vac heaters.

Going from 115VAC to 120VAC at the primary does not explain secondary going from 4VAC (or worse, 3 VAC loaded) to 6.2VAC .

[nosaj]

Going from 115VAC to 120VAC at the primary does not explain secondary going from 4VAC (or worse, 3 VAC loaded) to 6.2VAC .

After checking r95 an 96 ( had to unsolder one leg of each to test then resoldering them back in with it on the variac is when things looked better. Bad solder joint on r95 or r96?

jason