#124 Main Board Layout

[talbany]

. Thanks for the PS Board... Big help.....I have seen many variations as well here but none as exact as Martin's... I want to nail it exactly color caps color wires types of resistors everything..... So anyone out there has something to contribute that will help speed me up bring it....



Tony VVT

[ic-racer]

Here's the PS filter board as I make it out.

MPM

Fantastic! Thats the first time I have seen the power supply drawn up correctly. I made my PS board up just by looking at the pictures. I put it on the scanner, in case I ever wanted to make another. The measurements are just a guess based on the #124 pictures. When I did the #40 layout, I made it to scale, so that one can cut and drill the boards right from the drawing. Likewise it would be nice to have the #124 layout to scale.

The dimensions shown were for my build on the Natchanis chassis. A better guess at the actual size of #124's board is given later in this thread.

[ic-racer]

So anyone out there has something to contribute that will help speed me up bring it....

Tony VVT

Here is my unfinished #124 layout. Since the amp has long been completed, my incentive to finish this layout has diminished. You may be beyond this point already, but here it is anyway.

[ic-racer]

Here is some more stuff that may, or may not be of any benefit.

I took the pictures of the boards and removed the perspective and tweaked them in Photoshop. I imported these pictures into my layout program and used them as a guide for component location. Since I never completed the layout they may be of some use to you.

[ic-racer]

Just something to be careful of looking at the pictures. The #124 12v board has two 1k resistors of different brands. The #40 12v board has two resistors of different values (1k and 56k)

[martin manning]

Hey, this is good fun, and thanks for the kudos! ic-racer, you must have a BSRE (Bachelor's in Reverse Engineering).

I see that the Ceriatone layout has the PI grounded at the loop jacks... I have probably not squinted at the #124 pictures long enough, and maybe it is impossible to tell with all of the stuff running along the back wall, but this doesn't feel right to me. I'd think the correct ground point would be at 2, along with the filters that supply the PI and the speaker jacks. I can see what looks like a wire coming from the back to the lug there.

Since the loop jacks are ahead of the OD stages, I don't think they should be too close to the NFB. A really anal person would run shielded wire across the chassis, isolate the jacks, and take the ground over to the other inputs. But, I guess it works as shown, and I'm still learning here...

MPM

[talbany]

It will be to scale



T

[ic-racer]

I see that the Ceriatone layout has the PI grounded at the loop jacks...

Pretty sure #124 is grounded there. Gil has pointed out this is seen on other amps also.

[ic-racer]

[quote="martin manning"] I can see what looks like a wire coming from the back to the lug there.
/quote]

When I built mine I had the impression I knew every wire in every picture. But its easy to make mistakes and some things are not clear. Anyway, can you post the picture in question, lets have a look at it.

[martin manning]

Okay you are right, I see it now. The attached picture shows the black in the black-brown-green tie-wrapped bundle going to the return jack sleeve, and we're assuming those are the PI ground, Master wiper, and PI input, respectively. A little deja vu going on here... seems to me maybe this was discussed once before. So, I guess I'll update my board layout one more time.

The ground 2 point has the black wire from the B+2 and 3 filter caps, one of the filament ground resistors, and one other black wire coming from the rear. That black wire must be the ground from the 50/100W switch then, one there and its mate similarly to ground 3.

MPM

[ic-racer]

Okay you are right, I see it now. The attached picture shows the black in the black-brown-green tie-wrapped bundle going to the return jack sleeve, and we're assuming those are the PI ground, Master wiper, and PI input, respectively. A little deja vu going on here... seems to me maybe this was discussed once before. So, I guess I'll update my board layout one more time.

The ground 2 point has the black wire from the B+2 and 3 filter caps, one of the filament ground resistors, and one other black wire coming from the rear. That black wire must be the ground from the 50/100W switch then, one there and its mate similarly to ground 3.

MPM

Yes I agree with those findings. Its always nice having another set of eyes check things over. You still may find an error on #124 schematic if you look at the pictures close enough (I have looked at them pretty good, but I'm not perfect ). I was about half-way through my build when it was 'discovered' the send/return network had been interpreted wrong.

[martin manning]

Yes I agree with those findings. Its always nice having another set of eyes check things over. You still may find an error on #124 schematic if you look at the pictures close enough (I have looked at them pretty good, but I'm not perfect ). I was about half-way through my build when it was 'discovered' the send/return network had been interpreted wrong.

Yea, maybe, but so far you are batting 1.000.

Attached here is something I did to get started, and it may be of general interest.

Starting from your schematic I color-grouped the front and rear panel mounted components and the other parts that would conveniently or correctly mount directly to them. Then, the tube sockets and the parts mounted directly with or to them. Pretty much everything that is left is a large chassis-mounted component (transformer, e.g.), or goes on a board. The board mounted components sort themselves out pretty quickly, partly because I already knew the answer, but this seems like a systematic way to create a layout from a schematic alone.

MPM

[talbany]

Wow!! Plenty here to get me started.. I'll post the basics here in the next few days.. we can tweak it out a bit as I may miss a few details here and there... Thanks


Tony VVT

[ic-racer]

In keeping with making the layout to scale, here is the FET board. It would be nice if your software lets you superimpose the components over the trace, so that you can still see the whole trace and the holes. That way, a separate file with just the PC traces would not be needed, all the info could be in the same diagram.

In making this diagram, I did not know where the pins were on the back of the trimmer. So I indicated where the wiper needs to go.

***I need to redo the FET traces as I think it has 4 legs and as shown the legs are not in the correct order***

[ic-racer]

Looks like there were a few errors lingering in the FET portion of the #124 schematic. I suspect this had just been passed along, but looking at the pictures I see two 8k2 resistors.