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does anyone have a schematic for a marshall 5010 jm78-2 pcb?

Started by pinkjimiphoton, March 03, 2022, 05:57:19 PM

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pinkjimiphoton

hey now,
i posted this on another thread on the diystompboxes forum, my bro rob strand looked it over, and had the following to say:

Cool.  Thanks jimi and tassieviking.

I have *not* checked the trace/schem, however, the input stage didn't look 100% correct.

The no input cap is correct but the arrangement at the output of the first stage of IC1 looked wrong.
I posted the correction below.   The fix actually follows the other 5010 schem fairly closely, the only
difference is the other 5010 schem has an extra 100R on the output of IC1.


Bug on schematic Rev 1, 2022-03-19

(IC1 pin 7 goes to C4 (100p) and R6 (22k) as shown)

But then from IC7 pin 7 it should go,

IC7 pin 7 to C2+
C2- to paralleled C1 (47n) & R4 (10k)
other side of paralleled C1 (47n) & R4 (10k)
   to VR1.1 (ccw)
   and to IC1 pin 3

https://www.diystompboxes.com/smfforum/index.php?topic=35555.msg1243399#msg1243399

i have not had a chance yet to confirm anything myself. hopefully maybe tonite or tomorrow if i can get some time.

again, thanks! this nut's almost cracked.

i will get measurements too asap, promise.
what the hell ya mean it ain't fuzzy enough <static>

Tassieviking

I can not see anything wrong around C1, C2, R4, but the photo is not very clear to me.
Perhaps we could get another photo around that area that is a bit closer / clearer ?

I don't understand why Rob thinks it is wrong when he has not traced the tracks himself.
Comparing this circuit to another version of the amp is not possible when they are different.

I did find he inputs wired wrong, also R18 was connected wrong, the MIDDLE pot was reversed.
I have updated the faults and have now got Draft 2 ready.
I did enlarge and sharpen the image around C1, C2 R4 but I just cant make it out perfectly.
I really need a better photo of the tracks around C1, C2, R4, to make sure I got it right
There are no stupid questions.
There are only stupid mistakes.

Tassieviking

pinkjimiphoton, If I was to make up a PCB in KiCad, what changes would you like to see ?
Is there a better or modern Darlington that you would prefer ? TIP142 / TIP147 ??
I prefer a TO220, TO247 or similar at the end of the board, I could put a heatsink there or run wires to TO-3's
I always use stereo sockets for all jack sockets on PCB's, I like all the soldering points for mechanical strength.
I use Alpha 16mm pots on my projects, but it would put the alignment out with the Jack sockets (Height).
I might make up a footprint for 16mm and 24mm Alpha pots together, use what you like.
I like to use Moles KK254 and KK396 sockets for wiring off the PCB, but I usually solder the wires in anyway (No Sockets)

Here is an example of a board I'm working on, 12W / 12W reverb / 12W Mk1 / 12watt to 30watt amp (5010 poweramp)
There are no stupid questions.
There are only stupid mistakes.

pinkjimiphoton

that's nice work, bro!
i dunno what rob is seeing, so let me take a peek when i go downstairs.
i don't usually mess with amps much, more of a fuzzbox guy.... had to get a small production run finished yesterday,
will try and get to measurements etc this afternoon.
just woke up, crack of 1 pm. musicians.  :dbtu:

the darlingtons you're using are hip, and probably a lot easier to find than the originals!

i will try and answer all specifics this afternoon. thank YOU for your hard work on this!

the reverb 12 is one of my favs. i just finished restoring one recently, but modded slightly... using a 10" 8r celestion gives a bit more balls to it, and i had hacked in an fx loop and a touch more volume to it by adding in a simple guitarpcb.com board called a paramix.

https://www.youtube.com/watch?v=PM4GKTYwGwg

https://www.youtube.com/watch?v=_u83mHMtrco

more soon. beware of random f-bombs etc in my videos if easily offended. they're rarely SFW, and usually not particularly good ;)


what the hell ya mean it ain't fuzzy enough <static>

pinkjimiphoton

hey Tassieviking,

here's the deal. your schematic, the last one, has only one mistake.

r4 10k and c1 47n are in parallel. one node connects to negative side c2/gain pin 1, the other to pin 3 of the 1458.

other than that, matches the circuitboard i have on my bench as far as i can tell completely, and am absolutely sure the preamp is right other than that one spot.

its hard to see. there's a couple traces that may not look connected cuz of the way the board was laid out, and cuzza that sticker that i hadn't removed from an inspector.

here's a pic, i drew lines to show the connections, and filled in the blanks with the part #'s and values




















now... for measurements. board is 12.75" long by 4" wide. it sits on a 1 inch spacer centered at the back edge of the pcb.

from edge of board, j 1 center, between the mounting pins, is 11/16ths
j1 center is exactly 2".

pots are located at 3", 4.5", 6", 7.5", 9", 10.5" all 24mm

j3 is 11 14/16" from left edge of board.

28v center tapped transformer, 1 amp, like the hammond 166j28. it will fit the mounting holes in the original units.
what the hell ya mean it ain't fuzzy enough <static>

Tassieviking

I stand corrected on the trace at C1 and R4, I could not make that out on the pictures I was looking at.
I don't have much experience with audio circuits as I always worked in heave industry as an electrician.
I could repair 50kW DC drives for DC motors no problem, but never worked with audio circuits.

Anyway, here is Marshall 5010 PCB78-2 Draft 3 Schematic, please ignore the stereo input jacks.
I put stereo input jacks so I could start on the PCB in KiCad, I like the added strength of 50% more solder points.

There are no stupid questions.
There are only stupid mistakes.

pinkjimiphoton

what the hell ya mean it ain't fuzzy enough <static>

Tassieviking

I messed around with the PCB just for fun with your measurements.
This is what i came up with so far, but will change for what we want.
This is just mucking around a bit.
Are you after a very close copy of the original, or a better suited one for making a new layout ?
I could make the board 215mm (8-1/2") wide instead of 324mm (12-3/4") wide, just wide enough for the pots to fit.
Jacks would be connected with wires, It would make the PCB cheaper to buy, and still work as a replacement.
On the mock-up I added fuses for the transformer secondary wires, I prefer that.
I made a quick footprint for the pots so you can use Alpha 16mm or 24mm ones, just 2 extra holes is all.
There are no stupid questions.
There are only stupid mistakes.

pinkjimiphoton

that's beautiful!
personally, i don't like pots or jacks mounted via flying leads, and do like the full size board,
if just aesthetically.

but i'm stoked either way for your kindness and awesome work. thanks man!!!
what the hell ya mean it ain't fuzzy enough <static>

joecool85

Quote from: pinkjimiphoton on March 21, 2022, 01:32:06 PM
that's beautiful!
personally, i don't like pots or jacks mounted via flying leads, and do like the full size board,
if just aesthetically.

but i'm stoked either way for your kindness and awesome work. thanks man!!!

I'm fine with (and often prefer) on-board pots, but jacks should never be attached via PCB.  WAY too high failure rate.
Life is what you make it.
Still rockin' the Dean Markley K-20X
thatraymond.com

pinkjimiphoton

hey tassieviking, i think i found one other mistake...  i guess i was unclear in my description, and i just noticed it.

pin 1 of the gain pot connects to node of 10k and 47n on the 2.2uf tantalum side. so it's still off by that one connection. the 10k r4 and 47n c1 are in parallel. ONLY one side of them connects to pin 3 of the jelly bean.
the gain pot pin 1 connects to the other node, where the "input" of the rc network connects to the 2.2uf tant.

i did a q&d paint fix on it, this is how it needs to be:
what the hell ya mean it ain't fuzzy enough <static>

pinkjimiphoton

Quote from: joecool85 on March 21, 2022, 02:25:20 PM
Quote from: pinkjimiphoton on March 21, 2022, 01:32:06 PM
that's beautiful!
personally, i don't like pots or jacks mounted via flying leads, and do like the full size board,
if just aesthetically.

but i'm stoked either way for your kindness and awesome work. thanks man!!!

I'm fine with (and often prefer) on-board pots, but jacks should never be attached via PCB.  WAY too high failure rate.

yikes. ;)
to each their own.

i'm a stompbox guy, to me, i don't like ANYTHING on flying leads with a high gain circuit personally.
and in repair, i've done more repairs on stuff with leads than mounted to the board.

if it were tubes, where they're being subjected to mechanical stress and heat, i'd agree with ya, but imho board mounted is just as easy to fix and tends to mess up a lot less.

but whatever works for ya is good by me ;)

what the hell ya mean it ain't fuzzy enough <static>

Tassieviking

#27
Draft 4 and maybe final if ok with everyone.
I do have a few questions for pinkjimiphoton:
Are you happy with the numbering on the 2200uF Electrolytics ?
You had them as C23, C24, but to me it looked like C22, C23. (Not very clear though)
I marked the transformer as 14v = 14v secondary, close enough ?
I used the same Transformer number as the other 5010 schematic
Do you know what the Jack sockets are ? Cliff, Neutrik (I want the right footprint for the PCB)
Can't think of anything else right now.
There are no stupid questions.
There are only stupid mistakes.

pinkjimiphoton

yeah, you need a 14v-0-14v ac power supply, or 28vac center tapped. so yep, close enough.

i'm putting 6600uf caps in mine, they seem to run better with them. 2200 is ok, but quite a bit of ripple if ya run these hard. i tend to dime stuff, ....well.... i generally run the tone stack around 6, and the volume and gain dimed, anyways ;)

however i marked them big caps is how they are on the board, but there's parts that just are omitted here and there.. not even mentioned on the board. ;)

rob says i got that gain connection wrong, so i gotta check again WITH my beeper... but i think he's confusing the way the connection goes, cuz what you have now seems to match the drawing i had started and the board.

just to be sure, tho, i'm gonna beep it after dinner.
the jacks are like, identical to these:

https://www.taydaelectronics.com/hardware/6-35mm-1-4-plugs-jacks/6-35mm-1-4-stereo-insulated-unswitched-socket-jack.html
what the hell ya mean it ain't fuzzy enough <static>

pinkjimiphoton

i think i'm wrong, and rob is right, rev 3 is the proper one.
i haven't beeped it yet, but here's the connections, and tho i got r4 and c1 being in parallel right, it appears i dropped the ball, so my bad!

what the hell ya mean it ain't fuzzy enough <static>