5F6-a Bassman not working..

[silat]

I have tried everything and cannot get it to work right no sound from my speakers. I took loose all four of the speaker Jacks and only left one for testing to see if maybe I had something shorted.

[silat]

I am posting more pics it said my file sizes were to big .

[silat]

 

[PRR]

> no sound

Not even a faint hiss or hum?

[silat]

Nope! Maybe a slight hum.

[EL34]

Start here and report back after your have finished
http://el34world.com/Forum/index.php?topic=17701.0

[silat]

EL34, I am printing out that layout now to check against mine. I  wrote down my voltages and it looks pretty weird especially at the  rectifier. but aI have got some problems here. 

[HotBluePlates]

When you test for sound, makes sure your speaker is plugged into the jack with the switch on it. Otherwise, the switch shorts the speaker output to ground.

Was that really -122v on pin 5 of the output tubes? Or was is -12.2?

You should also be clipping your meter's black lead to the power transformer secondary center-tap (Red-Yellow), which ideally is grounded at the same place your 1st filter cap is grounded.

[silat]

It was  -122 which is pretty weird.

[silat]

Yeah I know about having my speaker plugged in I do not want to burn up my OT!

[HotBluePlates]

It won't damage your OT, you'll just get little-to-no sound from the speakers.

-122v seems unlikely from your amp's bias circuit. Check that you have the wire from bias circuit to output tube 220kΩ connected to the correct eyelet (not the one the bias diode is sitting in), and that you have a ground from the bias filter cap - & 56kΩ. If those were wired correctly, I'd expect the bias voltage to be divided down to the ~ -40-50v range.

[drew]

Give us more information about the amp.  Is it built from a kit?  What transformers did you use?

It appears you have a fault in the heater wiring to pin 9 of the first preamp tube.  It should be the same as the other two, not zero.

[plexi50]

Do you have the input jacks wired correctly? Plug instrument cable  into hi input and clip your DVM leads to the tip and sleeve of the cable.
You should read 1Meg just + or -. Then plug into the low input. You should read roughly 134K -144K.

[silat]

It is a tweed bassman kit. the transformers are from weber Pt W0227898 Int and the Ot. I Have new voltages.
     V1        V2       V3     V4         V5           V6
P1 192       61        291     0            0            N/A

P2  0           4        16     2VAC     2VAC         500

P3  1           3         50       506        519         N/A

P4 2VAC   2VAC      2V       504       507           -0

P5 2VAC   2VAC      2VAC    0           0            N/A

P6  215      359       281      500      506       -0

P7 0          359        15        0          2VAC      N/A

P8  1         356          50     78         88           501

P9  2VAC  2VAC    2VAC       

[silat]

I checked my wiring and had the 6L6's wired together on pins 8 instead of pin 6  it was my dyslexia.... 

[sluckey]

weber Pt W0227898 Int

No such PT. Maybe you mean W022798INT instead??? Did you get the standup bell covers for this PT?

V6 pins 4 and 6 should have a BIG AC voltage, more than 300VAC. I suspect this is correct since you show 500VDC on pins 2 and 8.

V4 and V5 shows 0V on pin 5. Yesterday you said you had -122V. Correct reading should be about -40v to -50v.
V4 and V5 pin 8 should be zero volts.

There are multiple bad voltage readings on all the little tubes!

Your filament voltage readings for all tubes is only 2VAC. That should be 3.15VAC.

I don't trust many of your voltage readings. Either your meter is lying or you are not checking voltages correctly. The DC voltage you read on pin 8 of V6 should be the highest DC voltage in the entire amp, yet you show higher readings on V4 and V5. What meter do you have?

[silat]

 Sluckey, Yes I did make sure I got the standup bells for the transformer. Ok somewhere something is not right it sounds like.  I have a craftsman volt meter.

[drew]

Can you take a better focused picture of the PT/rectifier area?  It's tough to see what's going on there.  Also, a clear, full length shot of the guts would help.

[silat]

Yeah, I will try to get some pictures  my laptop went down I am borrowing my wifes.

[silat]

More pics

[silat]

 

[silat]

 

[silat]

I was told my file size is too big when I uploaded the pics, but I thought it was the same as I used before.  So I have posted them individually.

[Willabe]

In the last picture there's a hole in the eyelet board on the far left side and it doesn't look like you have the blank insulator board underneath the eyelet board?   

[silat]

I do not because the chassis makes the pots too close and hit them so I put a thick carpet tape. I bought a cheap chassis and i am not very happy with it.

[Willabe]

Ok as long as nothing is shorting out to the chassis under the eyelet board?

[sluckey]

OUCH! There is 500VDC on that board. I would never use any carpet tape I've ever seen as an insulator for even 12V. If it's not a problem yet it will be.

[silat]

What do you suggest Sluckey? I have zero clearance...  if I use the blank board it pushes the board tight against the pots.  It is a  very narrow chassis.

[Willabe]

Looking at your earlier pics it looks like you have plenty of room? The blank board is only, what a 1/16"?   

[silat]

Ok I will put it under the board I do not want future problems to go along with my non working amp at the moment. I thank everyone for helping out. I hope you all stick with me on this and be patient with me?

[plexi50]

I know it's a pain to take pic's while you build an amp, but it is your documentation and only reference of confirmation of what you have done to look back on for any errors we all make at times when building an amp. I spend more time taking pic's to confirm my work than it does to build the amp. In the end it will save you a lot of grief and quess work.

[silat]

Alright, I replaced the tape with the blank board while I was there  I noticed I had a wire in the bias circuit in the wrong place. I moved it to where it belonged and rechecked  both my pins 5 on the two 6l6's and I now come up with -38 which is a lot better. But I have yet to get any sound. Any suggestions. I think it might have been plexi50 that suggested I do that. Thanks Plexi for that! Or whoever it was that thought of that.

[silat]

It was Hotplate Blues that came up with that! So Thank you !

[sluckey]

Recheck voltages on all filter caps and on every pin of every tube socket. Post the results. Double check your wiring. You just found one error. I'm betting there are others. Hang in there!

[Willabe]

Are you double checking your wiring with the what's in the link that Doug posted in reply #5 of this thread?

Best way to double check that I know of. 

[silat]

 V1              V2           V3         V4         V5           V6
P1 184        346         288        0            0            N/A

P2  4.8       1.2           23          2.9VAC     2.9VAC         512

P3  3          2.9            54           514       512         N/A

P4 280        250         277          510       510           -0

P5 4.9VAC   2.9VAC   2.9VAC    -38        -38           N/A

P6  280      350         277          510        510             -0

P7 0          350          17            2vac         2VAC      N/A      22UF filter caps 512,512,510,421

P8 1.3       348           54             87         45          512

P9  2.9VAC  3VAC    3VAC       

[Willabe]

Are you double checking your wiring with the what's in the link that Doug posted in reply #5 of this thread?

Best way to double check that I know of.

[sluckey]

Your voltage readings are still severely messed up! For example, V1 pin 4 is 280. V1 pin 5 is 4.9VAC. Well, pin 4 and 5 should be connected together and read the same voltage. That voltage should be 3.15VAC.

You either have major wiring errors, or your meter is lying to you, or you don't understand what you are doing and don't have an idea what the correct voltages should be.

[silat]

I am being honest. 4 and 5 are tied together and I just put the meter on them and got 3 vac. I might have touched 3 and 8 tied together and did not notice it.

[silat]

I Got it working at least but it is really low. I took the four speaker jacks loose and only hooked up one.
 

[HotBluePlates]

I Got it working at least but it is really low. I took the four speaker jacks loose and only hooked up one.

Do you have more than one speaker jack connected at all? If so, plug into the one with a switch (that is, the one with 3 lugs).

[silat]

Yeah that is the one I am plugged into.. I turned off the Normal volume pot and have the guitar plugged into the bright channel and it got loud like a bedroom amp but that is full blast. So I am getting there.

[plexi50]

If you are 100% certain that the underside of the board wire connections are correct then you should find the problem shortly on the top side. But if you have any reservations about the board underside then just get it out and flipped over and take some pic's.

If you cant find the problem on top then you really have no choice but to pull it out and conquer that puppy.
That's part of the fun in knowing for certain and ruling out any doubt.  Pull the board and you will be glad you did it sooner than later.

[silat]

 plexi50, I pulled the board  a couple of nights ago and put the blank board underneath because i had carpet tape sluckey had said it would not last so while I replaced that board I looked it over and took a picture..  I did not want to wonder about it.  I have sound but it should be where i could not stand it full blast. I cannot figure  what else is wrong unless I have a wrong resistor value  or a short or bad solder joint somewhere..

[jojokeo]

staying tuned to the same bat channel and...waiting to see what happens next!?  (sorry no time to help, heading out for sushi & will check back later) I love trouble shooting-capades...

[plexi50]

What are your cathode voltages on each of the preamp tubes?

[silat]

V1 Pin 8 pin3   V2 Pin 8  pin 3   V3 Pin8  pin 3
     1.4    1.4         358    2.1          53     53

[plexi50]

V2 Pin #8 358 volts dc?

Do this:
Pull V2 preamp tube. Measure all 9 pins and tell me what each pin is reading.

[silat]

pin 9         pin 8     pin 7    pin 6       pin 5           pin 4       pin 3   pin 2     pin 1
 
 2.9 VAC     0        401       401      2.9VAC            2.9VAC   0          0       400

[plexi50]

Ok lets start all over.  Why do you have two different colored leads coming from the choke? I see the customary black lead connected with the OT CT and connected to the first (2) 20uf filter capacitors. But then i see a white wire connecting to the 4.7k supply resistor. What is the story with that? It should be the second choke lead and black as well.