124 Layout Revised

[ic-racer]

Here is the layout for the OD relay.

[ic-racer]

Here is a picture showing how the wires to the presence and master are routed under the main cap board.

[martin manning]

Spotted another one...

The black ground wire from the presence cap to the FX return jack sleeve lug is missing. I guess you could label the FX and speaker jacks, too.

Then, looks like you've added a jumper from the OD cathode grounds to the 1 uF presence cap. If you have that, then you have to remove the jumper from the OD cathode grounds to the OD input trimmer or you will have a ground loop.

This is the part of the ground scheme that is unknown, since the under-board wiring is not visible. It all comes down to weather you ground the OD stages with the clean stages or with the PI.

Apparently it works with the OD stages grounded with the PI, has anyone built one up with OD and Clean grounded together?

MPM

[ic-racer]

Apparently it works with the OD stages grounded with the PI, has anyone built one up with OD and Clean grounded together?

MPM

From what I remember Gil wrote he does it that way and I would follow his lead on this one.

Question: Since the V2 cathodes are right there, do you also run them with that PI ground (to the SEND jack, like the diagram I posted)?


Answer: No.

Gil

[talbany]

Revised

[ic-racer]

Wow, it is really looking good!!

(That little tab on the FET component still points in the wrong way though)

[martin manning]

I guess I'm the ground police...

Pin 3 of the 5-pin XLR needs a ground wire going to ground point #5, which is a ground lug bolted to the chassis just above the upper-left PT mounting bolt, right about where the LM7812 is now.

The LM7812 leads are soldered to a three-point, center ground terminal strip that is attached just above the ground #5 lug, and there is a black wire going from the center terminal to the ground lug described above. That is the ground for the relay supply and foot switch LED power, and the LM seems to be grounded twice. You can remove the wire going from the center of the LM to the PT mounting bolt and the lug there.

It is lookin' good!

MPM

[talbany]

That little tab on the FET component still points in the wrong way though)

IC-
Which FET Componet are you talking about?

Also I don't mind making the correct changes really if everyone could do me a favor and please look over everything and give me all the changes they see at one time so I don't have to keep going back.. That way we can knock this thing out.. So far I have about 8 hours in this puppy.. Thanks so much

Also if someone has an accurate diagram or layout for the footswitch I'll be happy to add it to the drawing..


Tony VVT


T.

[talbany]

Revised again... Think we're gettin close





Tony VVT

[martin manning]

Tony,

Yea, sorry to be giving you stuff piecemeal. Probably can't be avoided unless a large block of time were dedicated to going through the whole thing systematically, and its likely none of us has that luxury. I've put many hours into doing the other boards, and I think there is just no way to get an accurate or even electrically correct result for a thing as complex as this without a lot of time spent. I really appreciate your effort!

ic-racer is talking about the FET device itself. It's index tab needs to point down instead of up, IOW, rotate it 180 degrees.

I got to looking at the PS board, and reposted my version from the "#124 main board layout" thread below (now improved with authentic text on the caps), which I think is dead-on. Yours has a tie-point eyelet and a jumper between the negative terminals of the two caps on the right missing, and the feed-throughs and hook-ups are a bit different. Maybe it would be easier to just swap out the whole board? Throw some silicone goop on there if you like!

The choke leads pass through the same grommet as the OT primary leads, which is not the same one as the secondaries (that is the one you have shown). This second grommet is just abut half-way along the PS board edge, and the choke itself needs to be rotated 90 degrees. The attached top-view photo shows all of this.

MPM

PS: The LM7812 needs a nut on its mounting lug, too.

[ic-racer]

I guess I'm the ground police...

Pin 3 of the 5-pin XLR needs a ground wire going to ground point #5, which is a ground lug bolted to the chassis just above the upper-left PT mounting bolt, right about where the LM7812 is now.

Actually from the XLR, the ground wire goes to the slide switches, (technically just to the OD switch, because of an omission by Mr. D) THEN, it goes back around to ground #5.

The "FET component" I mentioned is that 4 pronged NTE452 transistor on the FET board. They way I drew up the traces, the index tab has to be pointed in the right direction for it to work (based on the component datasheet)

[martin manning]

I guess I'm the ground police...

Actually from the XLR, the ground wire goes to the slide switches, (technically just to the OD switch, because of an omission by Mr. D) THEN, it goes back around to ground #5.

I didn't check the photo, and it looks like Tony's got it right. The police need to be policed too, eh?

MPM

[talbany]

Do you see the green and blue wires that have a wire cap on them just above the regulator LM.. Where does this go?



Tony

[ic-racer]

Thats the pilot light (LED) wiring.

[talbany]

MPM
Power supply is updated.. It was much easier to revise the the existing one rather than run the wires again.. FET's updated as well.. Didn't catch the notch on the board..Labeled the grounds 54321
As for the orientation of the choke.. I tried moving it to the correct spot and couldn't image it correctly looked like a pizza.. I want to keep it as clean as possible.. I think they get the point..
Also looking at Nicks OD relay board looks to me like its backwards.. Grounding it switches it to clean channel..
Also keep in mind that those doing a tubes up version need to wire the Rock/Jazz, mid boost, bright, flipped over otherwise they will be backwards.. Anything else..
ic-racer I thought you posted a nice rundown of the specs of 124 voltages etc..somewhere. If you wouldn't mind reposting this so I can add it somewhere on the layout would be nice to have.. Also anyone have a layout or diagram of the footswitch would also be an important part of the amp as well...

Updated again

Tony