Princeton Reverb

[Big chief]

Please help.  no voltage to heaters.  Tubes check good have voltage to rectifier tube
Replaced fuse. The only tube to light up is the rectifier 370 volts to tube

[shooter]

no voltage to heaters.

disconnect the heater string from the PT and check at PT 6.3 volt taps, got 6.3V??


leave disconnected and OHM each heater wire along the string.  So gator-clip one lead where it WAS connected to PT, then use other lead to probe the string.  repeat with Other wire

[Big chief]

Have 6.8 volts checking cross the wires from pt no volts at pilot light or 6v6 where heater wires start..no broken wires from tube to tube.
Volts tubes v1 pin 1 443 pin6 443 V2 pin 1 496 V3 pin 1 443 pin 6 443 V 4 pin 1 409 pin 6 460. V5 pin3 495 V6 pin 5 495 pin 3 495 V 7 pin 4 374 pin 6 374 pin 8 497
My friend that ask me to look at this stated the owner put a tube in wrong and that is what caused the problem (just info). This amp is a reissue with pcb
Sure hope you can help

[shooter]

it's 2 wires or traces, you don't need power, just an ohm meter like I sated already. follow one looking for an OPEN, repeat with 2nd wire, problem found

[Latole]

Wire must be broken or solder between the PT and pilot light . See layout

[sluckey]

That old '60s layout is useless for this amp.

Chief, change the filament fuse, F2. See attachment...

[dude]

Sure seems like a wiring issue, if you get 6.8v a/c at PT. Check if the pilot light is shorted internally.   
NOTE: OK, missed the PBC reissue

[Latole]

Wich Princeton Reverb is it  ? Reissue  or real vintage ?

[Latole]

Reissue :
Check connector at PCB, 7 amp fuse

[Big chief]

Checked voltage on each heater wire from pt only 1 wire had voltage
Jumped around fuse on circuit board still no voltage on heaters
This is a reissue 68 model Princeton reverb.  Friend told me the owner installed a tube in the wrong position and that caused the problem.   Any help would be appreciated

[Latole]

One side of heater printed circuit may be broken.

It is wire or printed circuit for heater ?

[Big chief]

Wires plug on to printed circuit removed wires from circuit tested 1 wire had 6.8 volts the other wire no volts both are heater wires from pt

[Latole]

Wires plug on to printed circuit removed wires from circuit tested 1 wire had 6.8 volts the other wire no volts both are heater wires from pt

Earlier you wrote ; "Have 6.8 volts checking cross the wires from pt 

[Big chief]

Yes the first time used multi meter  I checked the voltage with negative to positive I did not check each wire positive to ground only 1 heater wire has voltage if I’m right both heater wires have voltage separately sorry I’m frustrated trying to help a friend
Thanks

[shooter]

I’m frustrated

time for a break, gremlins feed on frustration, the more frustrated the more havoc they reek

[sluckey]

Yes the first time used multi meter  I checked the voltage with negative to positive I did not check each wire positive to ground only 1 heater wire has voltage if I’m right both heater wires have voltage separately sorry I’m frustrated trying to help a friend
Thanks

The correct way to check filament voltage is across the wires. DO NOT CONNECT ONE PROBE TO GROUND!

[Big chief]

I have checked cross the wires no voltage could the pt be the problem the 2 green wires coming from pt only 1 has voltage disconnected heater wires from pilot light to check possible short as the pilot light is fed from v6 no matter what I check can not find the problem.

[shooter]

Look at the schematic in Reply #8


DO NOT PLUG IN AMP


the transformer has a PLUG that connects to the PCB
unplug it 
OHM between P9 and P10 (heater windings)
It should be close to ZERO ohms

[sluckey]

     ***DO NOT CONNECT ANY METER PROBE TO CHASSIS!***

Chief, disconnect the two PT green wires from the board. Now connect your red meter probe to one green wire. Connect the black meter probe to the other green wire. Set meter to read AC VOLTS. Turn on the amp. You should have 6.3VAC. This is the only way you can accurately measure the heater voltage. Do you have 6.3VAC? If so reconnect the green wires to the board (P9 and P10) Doesn't matter which wire goes on which lug.

Now refer to the attached pic. Connect the red meter probe to WJ12 (TP33) and connect the black meter probe to WJ11 (TP34) Do you have 6.3VAC here?

Report your findings.

[Big chief]

Have 6.7 at wires no voltage Wj11 and Wj12
0.6 ohms across heater wires

[Big chief]

Is it safe as a test to jump direct from heater wires to to v6 where wires connect to tube socket

[sluckey]

Is it safe as a test to jump direct from heater wires to to v6 where wires connect to tube socket

yes

[shooter]

Is that bypassing the Fuse?


Has the fuse been verified since the PT has power and the test points don't?

[Big chief]

Fuses test good with ohm meter even bypassed with wire
First heater connection at w 11 w 12 no voltage other heater connection have 6.8 volts to v6 both white and black wire jumped direct to tube still no heaters light up
Switched wires did not work  maybe remove pcb and inspect connections

[sluckey]

Disconnect the PT green wires from the board. Disconnect the black and white wires from WJ11 and WJ12. Cut them if you have to. Now connect the black wire to the green PT wire and connect the white wire to the other green PT wire.

[Big chief]

Did what you said have sound coming out of amp should I leave that hooked that way or was that just a test  wow thanks

[sluckey]

Did what you said have sound coming out of amp should I leave that hooked that way or was that just a test  wow thanks

If I was doing that work I'd fix it properly. But that will likely involve lifting the pcb up to gain access to the bottom.

If you don't feel confident to fix it properly then leave it as is. But, you need to add two 100Ω resistors as an artificial center tap. The original resistors are on the board and are no longer in the circuit.

Can you post a hi-rez pic of that end of the circuit board? I want to clearly see WJ11 and WJ12,  and P9 and P10, as well as F2.

[Big chief]

I’ll try to take photo and post I’ll probably pull the board as I like to do things right
I’m an old man that have been around amps and guitars for over 70 years when they simple 

I really appreciate your time to help me

[Big chief]

See photo

[sluckey]

See attached...

The problem is in this pic. Wiggle the lugs at P9 and P10. Also wiggle the black and white wires at WJ11 and WJ12. Looking for anything that does not feel like a solid connection. Also check that F2 fuse with your ohm meter. Zero ohms is good. Anything else is bad. If bad, replace the fuse. OK to solder a jumper wire across the fuse if you can't find one. Lot's of amps don't put a fuse on the filaments.

One more thing to check before you pull the board. Check for zero ohms between P9 and WJ11. Check for zero ohms between P10 and WJ12. This will give you a good idea what to look for when you pull the board.

Now pull the board and examine that area for bad solder joints at the fuse, P9, P10, WJ11, and WJ12. Also look for any burned or cracked pcb traces associated with any of these points.