[Dillen]

TR17 C-E short?

Martin

[Dillen]

There could be many reasons, but that would be the first on the list.

Martin

[Dillen]

Did you fit the correct type of capacitor for C2103?
It must be a blue Philips/BC axial. Nothing else can be guaranteed to work.

Martin

[Dillen]

Well done!

Martin

[Dillen]

Since it does switch on, we can assume that the sensor pad circuit around TR21 is working.
The problem must be somewhere from R126 up to IC6. A broken copper trace, perhaps?
Have you checked R126? Those high-ohm resistors can go way high or even completely open.

You could lift one end of R122 and R126 respectively and cross their connections to see if the FM5 pad will then give you FM4 and the problem moved to the FM4 pad.

Martin

[Dillen]

So the FM5 lamp never lights up – even while touching the FM5 pad?
Was this problem present also before you started work?
Before you replaced lamps?

Martin

[Dillen]

Will it switch to FM5, if you touch the FM5 contact pin on the main PCB directly with your finger?

Martin

[Dillen]

The “lead” is what remains of an original indoor AM antenna.
In reality merely a plug with a 3m lead.

Here, most of the plug has gone missing, leaving only the lead and the pin.

Martin

[Dillen]

Beovision LX2800 has a RS-232 serial interface for a printer in the form of a DIN socket at the rear of the cabinet.
See page 18 (and 42) here:
https://bnoservice.nl/handleidingen/beovision-lx-2800.pdf

Martin

[Dillen]

And if that doesn’t work, you may need this for repairs:

https://www.beoparts-shop.com/product/beosound-century-ir-remote-control-pcb-service-kit/

Martin

[Dillen]

It could be an overvoltage problem on one of the supply rails.
Check for a shorted regulator. Begin with the one supplying the MM5450.
If so, repairs could be intensive.

Martin

[Dillen]

hcraig244 wrote:

set of capacitors and lamps ….

http://www.beoparts-shop.com

Martin

[Dillen]

davidross222 wrote:

New thread: what is best solvent to remove the gunk left by perished belts in tape drive??

IPA.
(Isopropanol alcohol, that is. – Not the beer).

Martin

[Dillen]

It’s B&O alright.
Not sure for what, though, but could be a RIAA, so perhaps an input adapter for a TV or a tape recorder.
Late 1960s or early-mid 1970s, I’d say.

And the 56K resistor has a bad solder joint. Perhaps the reason it was replaced.

Martin

[Dillen]

Apparently, the height matters to some extent – or Bang & Olufsen wouldn’t have made different stands.
Your speakers will play regardless – of course – though it may not be at the most ideal height, which is usually centered vertically around the height of your ears when listening (usually in a sitting position).

Also, – the S45-2 stands came in two versions; One has the vertical part assembled with a screw from below to the base part, the other is permanently welded.
I think the version with screw wouldn’t be strong enough for MC120.2 to be safe.

Martin

[Dillen]

All components can fail.

Is the TC9177P IC a typical problem and a well-known trouble maker IC?
– No.

Have I seen TC9177P ICs fail?
– Yes, once or twice in thirty+ years.

Considering the amount of work done to the module you show, I’d say check the work that was done as that alone could have caused the problem.

Oh, – and don’t forget to replace that speaker relay. Cleaning its contacts will only provide a temporary solution, and leaving it open like that won’t help it in any way.

Martin

[Dillen]

Beovox S45 (Type 6302) and Beovox S45-2 (Type 6312) does not suffer from foam rot as they use rubber surrounds.

Beovox S45 (Type 6427), however, does.
Fixable, though.

Martin

[Dillen]

These Beomasters (5500, 6500, 7000) will run a little warm at the cooling fins when powered up, even when not actually playing anything but silence.
This is mainly because the cooling fin also holds the power supply voltage regulators.

If the cooling fin is also warm in standby, it is most often caused by one or more
cracked solder joints at the amplifier power supply relay, keeping it from drawing and cutting power to the amplifiers, which means that the amplifiers will still be powered in standby.
Not good for the electric bill either.

The fan will normally only activate when playing at loud volumes with heavy passive speaker loads.

Martin

[Dillen]

Adjustment of what?

Martin

[Dillen]

Check the supply voltages to the Dolby ICs.
Particularly the Vref (a dead C2 wouldn’t be a first).

Martin

[Author]

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