express build progress pics

[ampmike]

Hey Guys,Just some pics,can you see if i screwed anything up at all.I started when Jim and Charlie did and Im moving a bit slow,Thanks Mikey

[ampmike]

Sorry one more,Mikey

[Big Jim]

Looks like you're making some headway Mikey. Keep up the good work!
Jim

[RJ Guitars]

Great looking start mikey. I am currently operating on the road from a notbook laptop so I can't see things well enough to do much of an eval. When I get settled on the far side of the world I'll bring it up on the big screen.

Press onward

rj

[M Fowler]

Mike,

Its looking good but I have to advise the use of pass through inserts or gromets for the wires going through the chassis. It really is necessary to do that for safety sake.

Mark

[ampmike]

Thanx Mark,I saw that too,I can get them right up the road from me at the hardware store.Thanks Mikey

[Big Jim]

Hey Mike, I would try splitting the grommet and working it in and see how it works, rather than redoing any wiring. That is of course you are pretty sure it's going to stay in there. Marks right. Chafing isn't good anywhere!
Jim

[ChrisM]

Is that a RJ chassis?
Also what kind of pots are those?

[Big Jim]

Since Mike didn't answer I'll do it. The pots are Clarostat from Westlabs. I have them in my Express and so far I like them alot. Similar to PEC. Stainless steel casings, conductive plastic wipers, high quality. They do however feel a little grainy. Yhis is my first experience with these pots so the jury is still out.
Jim

[ampmike]

Hey Guys,Well,of course I have problems,1 I had some diodes in wrong and blew the fuse,Then I did get heaters ok and the -25 on the power tubes pins 5,This is with pwer only on,After that I checked pins 1&6 on the preamps,Almost nothing there.So I guess Im stopped untill I get help.All testing was done with no tubes and only the power switch on,Any help is welcomed,Mikey

[ampgeek]

Hey Mikey,
Hit the standby switch to bring voltage to the rest of the circuit. The bias voltage is derived from the B+ supply upstream of the standby switch so what you are seeing is perfectly normal.

BTW, nice looking build so far!

Good luck,
Dave O.

[ampmike]

OK,I hit the switch but for some reason Pin1 on V1 still says 0,And all the way back to the mallory(looking down the far left top one) puts a o out when the others all put out voltage,Im wandering if I have a bad cap,I checked the wire under the board and its solid conection,Shouldnt the pos. side of that 20 uf cap read something with the switches both on,Thanx Man

[Gibsonman63]

I had a little confusion on the B+ circuit on mine. The red wires crossing over each other from the dropping resistors, the filter capacitors and the standby switch is a bit confusing on the layout drawing and with my eyesight, I had to zoom in tight to figure it out. Trace each of those out one at a time and check it against the schematic.

Check for B+ on the standby switch with the switch in the off position and work backwards if it is not there and forwards if it is.

Also, if you are blowing fuses, I would recommend building a light bulb limiter. It is really cheap and easy to build and will save you from buying fuses (and more expensive parts) while troubleshooting.

[ampmike]

Well Im not blowing fuses,Im did the limiter thing,I just dont know why Im not getting V1,Pin 1 a reading,The signal from the pin1 all the way back to the big cap seems to be all good but even when its all on that cap on the pos. conection does not seem to be putting out anything,Im think it should,now Im worried I screwed up the tranny or somthing,Wouldnt you think the cap should have a reading when the power and the standby is on?Thanx Man

[M Fowler]

Mike.

The cap could be bad, may have been destroyed when soldering close to the end on these wrecks cap stacks or taken out when voltage applied, or just plain was bad to start with.

Follow cap testing shown in another post as well as reforming if possible.

Solder a good cap parallel with the suspected bad cap and see if you get voltage reading to pin one after that.

Did you use a bulb limiter or variac on first power up?

Mark