Re: Marshall Stanmore Repair
I found interesting post regarding this PCB on the elektroda forum
[url]https://www.elektroda.com/rtvforum/topic3430940.html[/url]Re: Marshall Stanmore Repair<br />
...940.html[/url]
VanDivX
Member
Last Activity: 03-22-2021, 03:55 PM
Joined: 09-22-2019
Location: Toronto, Ontario
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Last edited by VanDivX; 02-19-2021, 04:28 PM. -
Re: Marshall Stanmore Repair
On top of that smd crap, there is also two sided pcbs... removing parts can easily rips copper pathways. You can replace those with a piece of wire like I did when I removed the diode bridge for testing - found it was OK but replaced it anyway (I guess you mean that big one, KBL 406).
You are a professional when it comes to these things, compared to me. I don't even know how the two sided pcbs work - it seems you don't need to solder on top because there is a copper 'neck' connecting the bottom to top pathways, right? Also find it annoying...Leave a comment:
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Re: Marshall Stanmore Repair
I feel with you.
As I posted last fall, my pcb blows fuses and I found that the MOSFET (10n60nz) on that big heatsink is shorted. I replaced it and when I powered up, the fuse held and I wanted to check if I am actually sending power in past the fuse and went to touch one meter probe to the solder point under the power connector and just as I touched it, it blew like if you short 120V AC. But it wasn't my doing, that replaced MOSFET blew up, shorted again. My hope for the board lasted all of one minute.
...Last edited by VanDivX; 11-17-2020, 05:16 PM.Leave a comment:
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Re: Marshall Stanmore Repair
That diode is D5, is labeled S3M and its marking strip is on the right side as in your picture, away from the transformer. I can post a picture tomorrow.
Somewhere back on this thread, someone posted a partial scheme and the diode is on it, also marked S3M....Last edited by VanDivX; 11-10-2020, 04:37 PM.Leave a comment:
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Re: Marshall Stanmore Repair
In the post #68 above here is a scheme where your coil would be at the bottom of it, joining two of those three 1000 uF caps. It is L1 as marked on the PCB.
I don't a goop there but because of those caps surrounding it, I can barely make out that there is any markings on the coil.
I would hazard to guess, if you didn't interrupt the coil wire, then it will be OK. Measure across it if you get some resistance, it will be OK. I can measure on it tomorrow to give you resistance value which I would guess will be close to short since the...Leave a comment:
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Re: Marshall Stanmore Repair
That's OK, myself also pop on here only once in a long while, like when checking my open tabs in the browser. It is nice when people return to say what worked for them.
They had no idea what was wrong with because they didn't troubleshoot it. Given how it is plastered with the gummy black goo, it was never meant to be fixed. Mine is not as badly sealed as what I've seen in pictures others posted here but still, it is a pain to work on. Double sided PCB is also not friendly when it comes to parts removal for testing and...Leave a comment:
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Re: Marshall Stanmore Repair
Hi, just dropped in, I have the same thing happening, posted on it last August or September here, then I put the troubleshooting aside and didn't get to it yet, even if in meantime some parts I suspected and ordered from China came in the post...
Your post motivates me to maybe start tinkering with it some more. I am pretty weak in measuring on electronic parts but I tested the diode bridge last fall and it looked OK to me. I ordered the FET transistor that sits near the power supply components and I think it could malfunction to...Last edited by VanDivX; 07-24-2020, 03:34 PM.Leave a comment:
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Re: Marshall Stanmore Repair
I wonder if you are still around, if you could report how the repair went. I am in Toronto and guess 'out of province' likely meant to Quebec, Montreal?
I took several months off trying to fix mine, maybe will give it another go since in the meantime I got some parts for it I ordered from China. My speaker blows fuse and I hope it is something wrong with P/S part of the PCB, like the bridge diode or the MOSFET...Leave a comment:
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Re: Marshall Stanmore Repair
Just a guess - the OP mentions in 'case' #3 'blown fuse' some ""standby mode" circuitry thrown in for European compliance"
Could someone have removed that transistor in some earlier 'repair effort'? It might well be superfluous but then again... again just guessing, maybe someone removed it, found it faulty but didn't get replacement and abandoned working on it?
As for my problem, I wait for the mosfet and rectifying bridge to arrive in mail but replacing them is just a...Leave a comment:
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Re: Marshall Stanmore Repair
Can one edit one's posts here? Like at least to correct some spelling? I don't see how to do that.
Anyway, I measured across the two yellow blocks either side of the smaller transformer and they measure 0.8uF, I suppose then they are capacitors then and are OK. One of them is marked as CX1 on pcb.
I tried to take picture of the markings on the 'transistor' mounted on the black heatsing right behind that big capacitor I removed for measuring and it says 'F' 1FO5BR FDPF 10N60NZ
Googling around, I found it is FDPF10N60NZ...Leave a comment:
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Re: Marshall Stanmore Repair
Hi there, new member... I have this expensive piece of hardware and when I opened it, I found the fuse blown but replacement blows again. Clearly I am the 'Case 3' in the original post - "no led, fuse blown".
My skills in this regard are very mixed, I know how basic electronic parts work but my radioamateur days ended when IC circuits came on scene. I did careful visual inspection but nothing looks bad. I was hoping for bulging capacitor top or something of the kind but it all looks OK.
I suspect some short in the...Leave a comment:
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