Marshall VBA 400 Bass Amp / No Power

[sluckey]

Alright! Moving forward now...   

[plexi50]

Wired up. Ready to flip on and see filament voltage. Any other thoughts before i proceed? Bon Voyagee!


.

[plexi50]

Bringing up on Variac slowly/ Wont work unless i plug the AC cord to amp first/////

[plexi50]

119 VAC. 6.53 filament voltage. All tubes are lit up. EUREKA!
Plugged in speaker and RL1 switch is working. Stop!

[plexi50]

Power and Preamp tubes lit up. Have not flipped standby yet.

[Willabe]

He didn't. He only had links 1, 3, 7, and 9 installed when he took those pics. That's the configuration for 230VAC operation.

Yes when he took those pictures but earlier he had a PT that was smoking hot. Could be why?


                 Brad      

[sluckey]

119 VAC. 6.53 filament voltage. All tubes are lit up. EUREKA!
PlugGed in speaker and RL1 switch is working. Stop!

Good stopping point. Now, do the world a favor. If you have a booklet of wire markers label all those transformer wires, ie, W15, W14, W12, etc. If you don't have wire markers then use a good permanent Sharpie and write the W# on the wire connector terminals.

Also, look at the wires for each transformer and tell me what color wire is on each W## terminal. I'll annotate the pdf and post it here. Might prevent some future frustration.

[sluckey]

Yes when he took those pictures but earlier he had a PT that was smoking hot. Could be why?

That's very likely. There's plenty of evidence that he had a jumper across every link at some time, maybe even at the same time. 

[plexi50]

Ok will publish all the wire colors by W numbers. Wow man! You are all King Bee's in my book. I didnt understand the link like i thought i did. Ok posting info in 5 minutes/

[plexi50]

Yes when he took those pictures but earlier he had a PT that was smoking hot
That was when i had a jummper wire across RL1 W7 & W6

Edit:

Thermal Switch Wiring is W3 & W4
Dual (EDIT: (Orange) 10VAC low voltage wires W6 & W7

W10 - White
W11 - Red
W12 - Gray
W13 - Blue
W14 - Black
W15 - Brown
W16 - Purple



W17 - W22

W17 - White
W18 - Red
W19 - Gray
W20 - Blue
W21 - Black
W22 - Brown

[6G6]

OK, I can stop worrying about that. 
I knew it would get sorted out.
I've been following the drama for days.

I do hope there are no other issuses, but they will be easier to tackle
if they show up now.

[plexi50]

Wowza! LOUD Monster Is Alive!

640VDC 6550 Plates
270r Screens are 320VDC
-36.3 grid voltage @ 10K grid resistors

Does that screen voltage look right?

[sluckey]

Screen voltage is OK.

I'M STILL WAITING ON THE REST OF THE TRANSFORMER WIRE COLORS!

So far you've only given me 6 wires for each transformer. I know there are 10 wires on the little transformer because I counted them. Don't know how many are on the big one. Give'em to me so I can go to bed.

[plexi50]

Ok im doing it now

[plexi50]

TI-65760C Filament Transformer

W12 & W13 are the (2) short black filament wires going to the power supply board
W6 & W7 are the (2) orange low voltage wires going over to the power supply board

EDITED: 1-8-2014
W17 - White
W18 - Red
W19 - Gray
W20 - Blue
W21 - Black
W22 - Brown
Total of 10 wires on the TI-65760C transformer

[sluckey]

W12 & W13 are the (2) black filament wires going to the power supply board
W6 & W7 are the low voltage wires going over to the power supply board

OK. Now give me the rest of the wires for the big transformer.

[plexi50]

Ok just a min

[plexi50]

TI-65765B Transformer Wires / Total (9) Wires

Thin black wire to PS board W21
Thin Orange wire to PS board W15
Thin Red wire to PS board W16

W10 = White
W11 = Red
W12 = Gray
W13 = Blue
W14 = Black
W15 = Brown

I will do all the OT and some other wire connections tommorrow and Doc the entire amp.
Might as well. Likely wont get another chance at documenting this amplifier

Thankyou millions for your genius and patience!

[sluckey]

I will do all the OT and some other wire connections tommorrow and Doc the entire amp. Might as well. Wont get another chance at doing this

Good idea. Here's the annotated pdf as promised. I'm done.

[plexi50]

Fantastic! I will post the rest to complete the last remaining W connectors.

Long story but i kept looking at the links and wondering WHY? would you have to cut and remove bussed links to change the voltage on an amp. So i kept thinking of a different wiring senario itself. 2 days ago i was thinking should i cut and or add links together to make the changes like you and SILVERGUN were pointing me to. Turns out thats exactly what you all were saying. I think wire swapping would have been a more normal approach when they made the amp.

But seriously this has been fun and painful all at the same time. This is what it's all about and what drives me.
Doug needs to install a Toll Booth for overtime charges. Saving that PDF now. Goodnight until next time*

[Willabe]

Long story but i kept looking at the links and wondering WHY? would you have to cut and remove bussed links to change the voltage on an amp. So i kept thinking of a different wiring senario itself. 2 days ago i was thinking should i cut and or add links together to make the changes

So are you saying that when you got the amp ALL of the likes where in place? Or was it set up for 230v with just those links in place?

            Brad     

[plexi50]

So are you saying that when you got the amp ALL of the likes where in place? Or was it set up for 230v with just those links in place?

When i got the amp the pic's i showed of the links were as i received it and it was linked for 230VAC. The later pic's from tonight (now yesterday) show the new links installed and the ones that were removed from the board. Man what a day. I did 4 amps total today. Im wiped out. This one was the real mind bender/

[HotBluePlates]

There's plenty of evidence that he had a jumper across every link at some time...

Gents, I'm 99% sure Plexi didn't put jumpers in all those positions.

Given the way the leads look from the back of the board, they're bent inwards as they would if mechanically placed prior to wave soldering. I think Marshall installs all the links, then clips off the un-needed ones to set the operating voltage for the intended country of distribution.

I'm banking on the links having been set for 230v operation this entire time until he removed all and wired for 115v. And the amp magically worked once that was done, so...

[plexi50]

Yeah HBP thats why i wasnt understanding the link thing. There were several links that had already been cut and the ends bent over. I just didnt get the whole senario of the missing links that appeared to have been there at one time or another. Is this amp the missing link?   Hell i cant sleep now. But i am very glad and thankful for learning something new and what i may expect in the future with other amps. Edit.

[SILVERGUN]

Wowza! LOUD Monster Is Alive!

sluckey    
I think your "people skills" are getting better  
 
 

[sluckey]

I think your "people skills" are getting better

HA! Just wait. I'll mess it up. You don't know how many times I have walked away from the computer in this thread to shake off my frustration.

Plexi50, if there's one thing to take away from this ordeal, it's this... LISTEN TO SILVERGUN!

He tried to steer you to the links early on, even colored them for you. But you didn't understand. It's OK to not understand. Especially when you're up against something you've never seen before. But instead of saying "I don't understand", you assured him the links were right. That sent us on a week long goose chase. And we would still be chasing if you had not finally taken the pics of the links.

So...    LISTEN TO SILVERGUN!   

[plexi50]

I should have pulled all the wires off the links from the start instead of peaking and looking through at the links. It may have become more obvious quicker what you all were saying. SILVERGUN you had it right all along. I see wild goose chase's in my future! Ha!

[SILVERGUN]

Plexi50, if there's one thing to take away from this ordeal, it's this... LISTEN TO SILVERGUN!

Whoa, whoa, whoa, whoa, whoa......hold your horses there...
So far I've only proven that I can read a schematic.  ....and draw pretty pictures
I try to limit my posts to things that I actually know something about  

plexi, there is one other option to consider....
we could convert it to "auto-link" so it senses input voltage and then auto sets the links for you....kinda like this (just a snippet,,,,I don't want to give you "schematic shock")
Now you can see why I could relate to that schematic  

[plexi50]

TI-65760C Filament Transformer

W12 & W13 are the (2) short black filament wires going to the power supply board
W6 & W7 are the (2) orange low voltage wires going over to the power supply board

EDITED: 1-8-2014
W17 - White
W18 - Red
W19 - Gray
W20 - Blue
W21 - Black
W22 - Brown
Total of 10 wires on the TI-65760C transformer

I just edited the W numbers for the TI-65760C filament transformer.

[plexi50]

Now you can see why I could relate to that schematic

Great eyeballs SILVERGUN. You know your stuff pretty good in my book

[sluckey]

I just edited the W numbers for the TI-65760C filament transformer.

Huh? Nothing changed.

[plexi50]

I saw this morning that both transformers has duplicate W numbers.
I Edited reply #114 as well and made a post earlier this morning

[plexi50]

OT Primary Top Row & W Links

[John]

I've been following this thread right along. Plexi, way to stick with it! Sluckey, SG and everyone else who hung in with him, good on yinz! 

[plexi50]

Thanks John! Credits go to the guys with more intel than me. Drama was mentioned. Talk about being on the edge! I was up until 1:45 a.m. this morning. It's hard to shut down after a major rush of info and making quick changes. The amp is done and sounds good. I had to retention all the 6550 sockets to keep the bottle pins in there socket. Speaking of sockets and pins these 6550 tubes have very thin pins on them. They are Marshall branded 6550's but i dont know who made them. Probably russia?