Traynor YBA1a recap went wrong

[aron]

Nothing catastrophic so far, but the amp doesnt work at all.
This is what i did,changed vol pots to 1mega,replaced can caps with jj32/500v,replaced other caps with equal value FTs put on a 3 prong cord, replaced stand by sw with old but functioning (at lest with my multimeter)switch.
The thing is the caps dont charge at all so I'm guessing the stand by (cuts the PT ct) is not working.The amp hums but does not make noise with the speaker attached,no hum ,only hi voltage hum from the trafo,connected the guitar and I only heard a slight thump very slight and when i went to discharge the caps there was no charge.tubes light up no red plates that I could see,no smoke no fireworks no fuses gone south.fan works fine so that part is ok,pilot light does not flicker,nice and bright red,
Im tired so im not working on it till tomorrow,that thing is heavy.
any suggestions?
Aharon
Thanks in advance

[sluckey]

Did it work before you fixed it?

[Colas LeGrippa]

in these amps, there are two caps in series in the filtering section, did you hook them right ?
did you touch the bias cap as well ?

[aron]

The amp was in the attic for 25 years unplayed,it used to work.Measured the secondary 800v way too high if you ask me  but should be half that if i measure the ct right ?nothing it reads nothing.The primary resistance reads 000 sometimes 007,I think its gone,caps should've charged something ,nothing,,actually the voltage under load was climbing slowly but got barely into 100v.
Changed bias caps and put the other caps as they were,even made a little diagram.A lot  of electric hum for my taste coming off the PT.did not heat up but was on only for a minute.
Aharon

[Colas LeGrippa]

800V is not too high. It will give 560VDC and with the current draw it will drop. remove all the tubes and fire it; check the voltages everywhere. One more thing: check the grounds. Power supply and power tubescathodes = one ground.

[Colas LeGrippa]

if you want less voltage, use the two yellow cauterized leads ( 5V, stock ) , install a GZ34 or dual 5Y3. On some YBA1A, the power tranny doesn't have the 5v tap though. On the two I had, there were.

[aron]

I thought of putting a copper cap in there to lower voltage a bit but the amp was designed for 400X1.14=560,so i don't know.I will do what you suggest and see what happens.Thanks

[timbertoes]

That Hum cant be good....

[timbertoes]

That .05uf cap on SW1.... maybe remove it.. not sure what they are doing...noise maybe.  looks large enough to trip a ground fault if that was in a receptacle.

[timbertoes]

800v - maybe the center tap connection is not there ?

[sluckey]

Measured the secondary 800v way too high if you ask me  but should be half that if i measure the ct right ?nothing it reads nothing.

Are you saying you do not measure 400v from each of the high voltage leads to the center tap lead?

If so, measure resistance between each of the high voltage leads and the center tap. What have you?

[MFowler]

Do you have the schematic?

[aron]

Thanks for the help  so far guys.
This is where I'm at now: Replaced on/off sw with DPDT,and slightly rewired that part now I get voltages that are in line with the schematics,plates560V,bias -43V,the caps charged fine and are distcharged by the 100k that even out voltage in the series caps.I plugged it to a cab and nothing but the hum from the power transformer is down to almost nothing now,I would say normal operation .So tomorrow I will take voltages from the preamp tubes down to the power tubes and see why there's no sound maybe I have a  bad tube,will do a replace and listen.
Aharon

[Beezerboy]

TRaynor tech support is really good. I had a yvc40 a couple years ago that crapped out & got tons of help, no charge

love Traynor amps

[timbertoes]

good news 

[aron]

I'll send yorkville a n email and see what they say thanks for the suggestion.
Aharon

[aron]

ok this is what i got some are different than what I got yesterday.

V1 cathode 2v
v1 pin 1 200v
v1 pin6 202

v2 pin 8 1.36v
v2 pin 1 370v
v2 pin 6 202
v2 pin 3 205v??

v3 pins 8,3 0v
v3 pin6 250v
v3 pin 1 240v
v3 pin 6 250v

power tubes pin 5 -41v
pins 4 could not measure meter goes crazy with tube in
pins 3 same
the 1K 10w resistor feeding this pin measures 550V

with the tubes in one leg of the OT seems not to have power.
Tried 2 sets of tubes ,the ones in the amp and a set from 2 Nos boxes I had westinghouse 6ca7

[Colas LeGrippa]

REMOVE THE OUTPUTE TUBES and take the voltage readings
check pin 5 of output tubes: there should be approx minus 50V.
the prob comes from the amp section : definitely a problem there

[aron]

thanks I will do that and report back.
Aharon

[aron]

ok this is what i got some are different than what I got yesterday.

V1 cathode 2v
v1 pin 1 200v
v1 pin6 202

v2 pin 8 1.36v
v2 pin 1 370v
v2 pin 6 202
v2 pin 3 205v??

v3 pins 8,3 0v
v3 pin6 250v
v3 pin 1 240v
v3 pin 6 250v

power tubes pin 5 -41v
pins 4 could not measure meter goes crazy with tube in
pins 3 same
the 1K 10w resistor feeding this pin measures 550V

with the tubes in one leg of the OT seems not to have power.
Tried 2 sets of tubes ,the ones in the amp and a set from 2 Nos boxes I had westinghouse 6ca7

Replaced C8 coupling cap and read voltage on pins 3 and 8 of phase inverter now I have 45V instead of 0V,
if I can get the nerve to plug in now and see if it works.....
Aharon

[aron]

Do you have the schematic?

Thanks a million MFowler for providing the closest schem and layout to the model I have.
Aharon

[MFowler]

Your welcome, now go enjoy your amp.

[aron]

Amp is working fine now ,thanks to everybody that helped.
Aharon