Hello I received a Marshall Stanmore speaker with a damaged converter from a colleague for repair (he himself got this speaker as part of the settlement and does not know its past). The diagram for this model is practically unavailable, so I am asking you to identify the elements: U1 - it had a...

The typical diagram for this circuit will be helpful, as well as the application note of the SG6841SZ - a practical equivalent (note, a different value of the RI-pin 4 resistor = 33 k?, see page 11). You must identify the individual elements based on them and recreate the diagram of your power supply.

Hi I read on mine ob2269cp, R18 and R104 are marked R100. Take a look at R10 and R19, DZ3. They have all been broken for me. Good luck I can't do it, I'm French, I don't speak Polish.

I have the same problem: r104 and r18 was burnt and i cant read anything.

Hi, i have the same problem, no power, but i have all the component good, i can help you with the problem if you want, but i need to know something about the tristar 13030122, about the pin conf, because maybe that is the problem in my case. best regards

This is not the same problem, but similar only because of damaged resistors.

I have one at my workshop r104 and r18 - 10 ? u1 - fqpf10n60c for me it is burnt u15 (power amplifier) could you give me what element is it?

Dear, I have the same problem, but I change the u15 ic and nothing works, I have problem I think with the Tristar transformer, can you tell the voltage of that? Best regards

One must measure these voltages present in the system and verify with catalog data. This will determine the power status. link page: 6.3 Recommended Operating Conditions

Help me, my Q7 missing, what number?

It may be useful, the resistor R18 is marked R100. I am attaching photos, taken from the equipment I repaired, where the 220uF / 35V electrolyte died.

[Solved] Identifying Components of Marshall Stanmore Speaker: U1, R104, R18 - OB2268CP or OB2269CP?

DJ Davi 45774 11

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#1 17032225 12 Feb 2018 18:50

DJ Davi DJ Davi

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Post #1
17032225 12 Feb 2018 18:50

Hello
I received a Marshall Stanmore speaker with a damaged converter from a colleague for repair (he himself got this speaker as part of the settlement and does not know its past).

The diagram for this model is practically unavailable, so I am asking you to identify the elements:
U1 - it had a burned hole. I was able to read the designation OB226. I suspect it might be OB2268CP or OB2269CP. Unfortunately, I am not sure, because the one that was there (the one with the burned hole) had traces that it was soldered and could be wrong.
R104 - unfortunately, nothing can be seen on this resistor.

R18 - this resistor was missing, it was on the other side of the board.

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#2 17044585 17 Feb 2018 21:29

aaanteka aaanteka

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Post #2
17044585 17 Feb 2018 21:29

The typical diagram for this circuit will be helpful, as well as the application note of the SG6841SZ - a practical equivalent (note, a different value of the RI-pin 4 resistor = 33 k?, see page 11). You must identify the individual elements based on them and recreate the diagram of your power supply.

Attachments:

iro33.0001.b5_sg6841v2.1.pdf (533.79 KB) You must be logged in to download this attachment.
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#3 17053877 21 Feb 2018 19:32

Lolo81700 Lolo81700

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17053877 21 Feb 2018 19:32

Hi
I read on mine ob2269cp, R18 and R104 are marked "R100".
Take a look at R10 and R19, DZ3. They have all been broken for me.

Good luck
I can't do it, I'm French, I don't speak Polish.
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#4 17180389 21 Apr 2018 16:20

pazenz pazenz

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Post #4
17180389 21 Apr 2018 16:20

I have the same problem:
r104 and r18 was burnt and i cant read anything.
#5 17265773 08 Jun 2018 21:57

mattpalominos mattpalominos

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17265773 08 Jun 2018 21:57

Hi, i have the same problem, no power, but i have all the component good, i can help you with the problem if you want, but i need to know something about the tristar 13030122, about the pin conf, because maybe that is the problem in my case.

best regards
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#6 17274697 13 Jun 2018 20:32

aaanteka aaanteka

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17274697 13 Jun 2018 20:32

pazenz wrote:
I have the same problem:
r104 and r18 was burnt and i cant read anything.

This is not the same problem, but similar only because of damaged resistors.
#7 17299481 27 Jun 2018 11:53

harnol harnol

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17299481 27 Jun 2018 11:53

I have one at my workshop

r104 and r18 - 10 ?
u1 - fqpf10n60c

for me it is burnt u15 (power amplifier) could you give me what element is it?
#8 17299588 27 Jun 2018 12:56

mattpalominos mattpalominos

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17299588 27 Jun 2018 12:56

Dear, I have the same problem, but I change the u15 ic and nothing works, I have problem I think with the Tristar transformer, can you tell the voltage of that?
Best regards
#9 17301796 28 Jun 2018 15:42

aaanteka aaanteka

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17301796 28 Jun 2018 15:42

One must measure these voltages present in the system and verify with catalog data. This will determine the power status.
link

page: 6.3 Recommended Operating Conditions
#10 17429330 08 Sep 2018 14:04

Kimera Kimera

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17429330 08 Sep 2018 14:04

Help me, my Q7 missing, what number?
#11 17445259 17 Sep 2018 15:33

Darekg Darekg

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17445259 17 Sep 2018 15:33

It may be useful, the resistor R18 is marked R100. I am attaching photos, taken from the equipment I repaired, where the 220uF / 35V electrolyte died.
#12 19305738 08 Mar 2021 21:29

DJ Davi DJ Davi

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Post #12
19305738 08 Mar 2021 21:29

The damaged U1 chip is OB2268CP. The resistors I asked for are 10 ?. In addition, unfortunately, I had to replace the power terminal, after which the speaker returned to work.
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Topic summary

✨ The discussion revolves around identifying components of a Marshall Stanmore speaker, specifically focusing on the damaged U1 converter and resistors R104 and R18. Users share insights on the U1 component, suggesting it is likely an OB2268CP, with some uncertainty regarding the exact model due to previous damage. Resistor R104 is noted to be marked as "R100," while R18 is reported missing. Several users report similar issues with burnt components and offer advice on troubleshooting, including checking voltages and replacing damaged parts. The conversation highlights the need for a schematic diagram for accurate repairs and mentions the SG6841SZ as a potential equivalent for U1.
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FAQ

TL;DR: How do I fix a dead Stanmore SMPS? "You must identify the individual elements" using the typical diagram; RI on SG6841SZ = 33 kΩ. [Elektroda, aaanteka, post #17044585]

Why it matters: It lets DIYers and repair techs correctly ID U1, R18, and R104 to restore power safely.

Quick Facts

U1 confirmed as OB2268CP in a successful Stanmore repair. [Elektroda, DJ Davi, post #19305738]
Some units show U1 marked OB2269CP; verify your board revision. [Elektroda, Lolo81700, post #17053877]
R18 and R104 marked “R100” on certain boards (low-ohm shunts). [Elektroda, Lolo81700, post #17053877]
Other repairs reported 10 Ω for both R18 and R104; double-check before ordering. [Elektroda, DJ Davi, post #19305738]
Common weak point noted: 220 µF / 35 V electrolytic capacitor failed, causing issues. [Elektroda, Darekg, post #17445259]

What is U1 on the Marshall Stanmore power supply?

U1 was identified as OB2268CP in a confirmed repair. "The damaged U1 chip is OB2268CP." Check your PCB revision and markings before ordering the controller. [Elektroda, DJ Davi, post #19305738]

Could U1 be OB2269CP on some Stanmore boards?

Yes. One owner reported U1 marking as OB2269CP. "I read on mine ob2269cp." Always verify the exact printed code and package on your board. [Elektroda, Lolo81700, post #17053877]

What is the value or marking for R18?

On working units documented, R18 is marked "R100." That denotes a low-ohm current-sense shunt near the SMPS section. Inspect location and compare against high-resolution board photos. [Elektroda, Darekg, post #17445259]

What is the value or marking for R104?

R104 is also marked "R100" on boards matching that layout. The same user confirmed both R18 and R104 with the R100 mark. [Elektroda, Lolo81700, post #17053877]

Are there boards where R18 and R104 are 10 instead of R100?

Yes. A successful repair reported both resistors as 10 . Confirm your PCB revision and surrounding circuit before sourcing replacements. [Elektroda, DJ Davi, post #19305738]

I replaced U1 and key resistors, but it still wont power. What next?

Check the AC power terminal and its solder integrity. One repair only succeeded after replacing a faulty power terminal in addition to U1. [Elektroda, DJ Davi, post #19305738]

What is U15 (the power amplifier), and what should I verify around it?

The thread references TIs TAS5342A. "One must measure these voltages present in the system and verify with catalog data." Confirm amplifier supply rails and control pins before blaming the transformer. [Elektroda, aaanteka, post #17301796]

How do I safely troubleshoot the Stanmore SMPS?

Recreate the PSU around U1 using the typical diagram and SG6841SZ application note.
Replace burnt parts, then power via a current limiter or variac.
Measure controller and output rails, and compare against the reference design. [Elektroda, aaanteka, post #17044585]

What is Tristar 13030122 and how do I find its pins?

Its the main flyback transformer. Pinout isnt published. Trace windings with continuity, then map primary, auxiliary, and secondaries using the typical application diagram as a guide. [Elektroda, aaanteka, post #17044585]

Do burnt R18/R104 always indicate the same root cause?

No. A moderator noted such cases are only similar by symptom. Treat each board independently and verify surrounding parts and rails. [Elektroda, aaanteka, post #17274697]

Could 1cU11d be a MOSFET like FQPF10N60C on some revisions?

Yes. One report listed U1 as FQPF10N60C. Designators can shift between revisions, so confirm whether U1 is the PWM IC or the switch. [Elektroda, harnol, post #17299481]

Which electrolytic capacitor commonly fails in this PSU?

Check the 220 8F / 35 V electrolytic on the SMPS side. A failed cap there was documented and replacement restored function. [Elektroda, Darekg, post #17445259]

Which nearby small parts often fail together with R18/R104?

Inspect R10, R19, and DZ3 on the primary side. One user found all three broken alongside the low-ohm shunts. [Elektroda, Lolo81700, post #17053877]

If I substitute SG6841SZ for OB226x, what should RI (pin 4) be?

Use 33 kA for RI on SG6841SZ as guided. That value differs from some OB226x implementations, so adjust only when using SG6841SZ. [Elektroda, aaanteka, post #17044585]

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