Marshall Stanmore Repair

[Walzzu]

Re: Marshall Stanmore Repair

Could someone tell me the cold side voltages coming out of the transformer?
Hot side is completely buggered, so I think i will bypass it and use different switching psu.
My tristar transformer is showing opens.

[DeeJayAlex]

Re: Marshall Stanmore Repair

This speaker barrel has 3 outputs
# 2x14v and 1x30v

[Walzzu]

Re: Marshall Stanmore Repair

This speaker barrel has 3 outputs
# 2x14v and 1x30v

Hmm... Which voltage should go where?
Two first are the grounds but what are the other 3?

Thanks in advance.

[DeeJayAlex]

Re: Marshall Stanmore Repair

#3-30v DC
#1 and 2-14v DC

[ceedjay]

Re: Marshall Stanmore Repair

Hi.
I have successfully repaired two stanmore. Both had identical faults. 220 ohm resistor to optocoupler burned. I have replaced all capacitors on the hot side. I have changed Mosfet,pwm ic, various resistors including 0,1 ohm shunt. I have replaced everything between pwm ic transformer output and the pwm ic. All diodes except the full bridge. All rectifier diodes after the 3 transformer output. 7812 and power amplifier. Both are now working but one of them have a high pitch transformer whine that also leaks into the sound. If I mute the sound the whining can be heared very clear out of the speaker.

Does anyone have any idea what i could do?

I have changed all 1000uf,470uf and 220uf capacitors as well.

Regards

[ceedjay]

Re: Marshall Stanmore Repair

.

[ceedjay]

Re: Marshall Stanmore Repair

Hi.

I have tried to move the transformer between the two and the whining is not moving. This means that it is not the transformer that is "faulty". If i remove the rectifier diode on the 14V line that feeds the LM817 the whining disappears. Everything is working so what can be wrong, maybe something on the 5V?

Regards

[TimelessTech]

Re: Marshall Stanmore Repair

Hello,

I'm not sure if this thread is still active, but my Tristar 13030122 is as shorted as can be and I hoped that maybe someone on here knows a suitable replacement part for it. Maybe via Aliexpress or something. Kind regards

[hann]

Re: Marshall Stanmore Repair

how did you know that its shorted?

[Arl96]

Re: Marshall Stanmore Repair

Hi, I'm from Argentina. Does anyone know what are the models of the transistors marked in the photo? I have received a Marshall Stanmore team with the lack of these two

[SkyHeart]

Re: Marshall Stanmore Repair

D8: Fmg23s
u5: Lm317t

[NokLa]

Re: Marshall Stanmore Repair

Hello, who can help with this chip?

[SMDFlea]

Re: Marshall Stanmore Repair

Hello, who can help with this chip?

Parts with an equals sign = are usually made by Richtek https://www.badcaps.net/forum/showpo...84&postcount=2

It could be a Richtek RT9114B .Check the pinout carefully.

Datasheet: https://cdn.badcaps-static.com/pdfs/...0b114cc4ee.pdf

.

[Wetterstrand]

Re: Marshall Stanmore Repair

Hi friends!
I have an issue with a fried R7 on my board. Tried to replace it but the new one starts to melt almost immediately.
Any ideas on what the main cause could be? R6 is still ok and brings the correct resistance.
I'm currently novice, but soon pro Thankful for all the help I can get

[Hombre]

Re: Marshall Stanmore Repair

Your audio ic looks quite burned, on it's pins, i assume at least some of the ceramic caps around ic are measuring low resistance across the. If yes lift IC and check again for resistance on surrounding ceramic caps, if it went up your IC is toasted, and that could be a reason why R7 is burning

[janne911]

Marshall Stanmore repair

Hello,

I have had a defect Marshall Stanmore (first edition) for a couple of years now that I meant to repair. However I haven't been able to find anyone with the similar issue until recently on youtube. However no suggestions to where I should begin troubleshooting.

Have anybody had the similar issue and possibly a fix for it?
Suggestions to where I should start also appreciated.

Video of issue : https://youtu.be/vft56VFffi0?si=lgFmQAfKRaJ3-lnF

Best regards,
Janne

[temaplav]

Hello, at the beginning, the 220 Ohm resistor (standard situation) and the 12V stabilizer were burnt. After replacement, it turned out that the sound amplifier also burned out. After replacing it, everything worked,
BUT THERE IS A DEFECT:
1. When turning the volume knob to the minimum, the power supply is rebooted (I send the signal via bluetooth). Through aux, the same situation.
2.
The same situation occurs when I press pause on the phone from which I send the signal.

The main voltage of 30V drops to 8-9V, due to PWM
After the automatic reboot of the power supply unit, everything continues to work.

[Hkekkonen]

Hello everybody!

My Stanmore is EU model.

I had it on standard mode, not standby(power saving). And i forgot to turn it off. Not sure for how long, maybe week or two. Once i realised, light was gone and it would not power on. Who uses power saving mode anyways if there is an option? Now it decided to force it self into it!

Fuse was ok. Visually nothing seemed to be burnt/defect, until i inspected it with microscope. C233 (220µF 25V capacitor) had two holes at the bottom part and some tiny debris close by. Replaced it with 330µF 35V, because it was closest i had.

Well that didn't solve it, still nothing. I used thermal camera and only place with higher temp, than surroundings was near optocoupler 35°C. By reading this thread, i decided to replace the C4 (220µF 25V capacitor).

It works again! 🎉

Thank you all for sharing your knowlidge and the different issues with Stanmore speakers.

P.s i have it on standby mode now.

[temaplav]

Please tell me the nominal value of the ZD5 zener diode

[Hkekkonen]

Hello everybody!

C4 (220µF 25V capacitor)

Sorry its C4 (3.3uF 50V capacitor)