Marshall Stanmore Repair

[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

[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

[ceedjay]

Re: Marshall Stanmore Repair

.

[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

[DeeJayAlex]

Re: Marshall Stanmore Repair

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

[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

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

[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

Hello,
on mine R96 is 10kOhm, (labeled "01C")

Do you know / could you check the values of ZD1 and ZD3 please if it is still open ?

Regards

Thank You for reply!
ZD1 and ZD3 seem to be ok(0,7mV on diode check)
they are zener diodes, which unfortunately I don't know what value they are
Soon I will start to repair it and if it is successful I will check the voltage drop of the zener diodes so that we can figure it out and I will let you know.
Regards.

[DeeJayAlex]

Re: Marshall Stanmore Repair

can you post a picture of the location?

The Location of R96

Thx.

[StephE]

Re: Marshall Stanmore Repair

Hello guys,
R96 is burn can you help me with its value?Thx

Hello,
on mine R96 is 10kOhm, (labeled "01C")

Do you know / could you check the values of ZD1 and ZD3 please if it is still open ?

Regards

[StephE]

Re: Marshall Stanmore Repair

Hello,

did you ever figure out the values/types of the three diodes ?

I have the same problem.
And lots of leaking caps.

Regards

[SkyHeart]

Re: Marshall Stanmore Repair

Hello guys,
R96 is burn can you help me with its value?Thx

can you post a picture of the location?

[DeeJayAlex]

Re: Marshall Stanmore Repair

Hello guys,
R96 is burn can you help me with its value?Thx

[SkyHeart]

Re: Marshall Stanmore Repair

Hello Guys,

it's me again trying to fix this Stanmore speaker mess, after changing a lot of components I was able to fix the power issues, the speaker comes on, lights are on, Bluetooth connects fine, when I play music sound comes for few seconds then I will hear 2 or 3 loud static from the speaker and sound disappears.

if anyone had a similar issue and was able to fix it please do share the information, I did change the TAS5342A IC.

[SkyHeart]

Re: Marshall Stanmore Repair

I think it's an Inductor not a resistor, for me it's the first time I see an Inductor in the shape of a resistor
it's been a while since last time I worked with Electronic it's been more than 15 years.

thanks for the help guys.

[SkyHeart]

Re: Marshall Stanmore Repair

Hi Folks,
I was finally able to find the issue with my Stanmore, after changing the 12v regulator which is in the middle of the PCB (KIA 7812A) i found out that it's not getting any input current, had to remove it again to trace the input which is feed by L7 it looks like a normal resistor it was a bit toasty, I'm not sure why the numbering on the PCB says L7.
my issue is number 2 from the first post, everything works without sounds output.

I changed that L7 with a normal 47ohm resistor and I got sound.

attaching a picture of L7 location.

[SkyHeart]

Re: Marshall Stanmore Repair

Hi.
My friend bought this IC from two different sellers they were new, At the first seller after replacing this IC there was no sound , bought 2 pcs and none of them worked, when he bought from another seller another two IC the IC was working properly, my friend said that there are a lot of fakes of this IC . And you have to be careful when buying.

Thank you kros for the information,

I got the amplifier IC's from mouser.com which is a very known website for selling electronic parts so I don't think they are fake.

[kros]

Re: Marshall Stanmore Repair

Hey @Chris_J
were you able to fix your issue?
I also replaced 7812 IC and the D7 including the TAS5342A IC, R23 and 3.3 cap but still no sound, I can pair with bluetooth and everything seems to work but still no sound coming.

Hi.
My friend bought this IC from two different sellers they were new, At the first seller after replacing this IC there was no sound , bought 2 pcs and none of them worked, when he bought from another seller another two IC the IC was working properly, my friend said that there are a lot of fakes of this IC . And you have to be careful when buying.

[SkyHeart]

Re: Marshall Stanmore Repair

Update:
The power amplifier was fried and the 7812 IC together withthe shorted D7 located underneath. Everything replaced except the amplifier.

The unit started up and this time the bluetooth worked as well Could easy pair it so there is hope for the unit but we see when I receive the power amplifier.

The amplifier IC has the marking 42TTI A87CG4 (?) but someone else suggests that it could be a TAS5342A IC?

Has anyone information what the amplifier IC could be?

Hey @Chris_J
were you able to fix your issue?
I also replaced 7812 IC and the D7 including the TAS5342A IC, R23 and 3.3 cap but still no sound, I can pair with bluetooth and everything seems to work but still no sound coming.