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The warm amplifier section points to a bad idle current trimmer.
Replace the trimmers (there is one for DC offset as well) and adjust them as
mentioned in the service manual.
– Or grab a kit that also contains new capacitors and a slight upgrade to the signal path.
Kit here.
Other parts here.Martin
Two different tape drives were used in these autoreverse decks.
One type has a belt-driven tape motion sensor.Martin
I agree.
And for soldering in areas where vibrations are part of the
day (portables, car stereos, speakers etc.), I like to use solder with a hint of silver.Martin
Bad tweeter?
Mixed up orange wires for the midranges – or wrong polarization(s)?Martin
Don’t get me wrong, but if you cannot see your way out of removing the screws for
the bottom plate, you may want to consider if this repair job is for you.
Perhaps it would be better if you leave it to someone with experience and training etc.Martin
3 December 2023 at 10:52 in reply to: Restore or upgrade Beolab / Beovox Penta Crossovers MK1 vs MK2 #34222Keep in mind, that if you replace electrolytic capacitors with any other type,
the new capacitors ESR will be (often very!) different – typically lower, leading to
different filter characteristics (and potentially other issues).
In speaker crossovers this will in many cases require a new calculation of the
filters, as the ESRs (equivalent series resistances) will have been taken into account in the original calculations as the (frequency dependent) resistors, they are.This is often the reason why owners experience, that their speakers sound “different” after changing capacitor types. The change in sound comes, not as much from the change in
type of capacitor, but from the fact that the filter properties were changed.Removing a few ohms ESR in f.e. a series capacitor for a 4 ohms tweeter, makes a lot of difference!
– Also for the load put on the tweeter, – that may not agree that it was such a great idea.The general speaker impedance etc. will also be different (typically lower!).
Martin
Apparently a major malfunction.
Can you tell if something burned inside? – And what?
Wrong mains voltage setting?Martin
What Filip said.
And there is a convenient kit for the servo board for exactly this.
Here.Martin
Capacitors, capacitors and capacitors.
Martin
It will need a rebuild. They all do by now.
New electrolytic capacitors. Replace like for like type-wise.
New trimmers incl. adjusting.Martin
The end switch should not be reached at the end of playing a record.
It should only be reached if no record is found.End of record is indeed optically sensed using the ruler.
Has the main board been rebuilt with new capacitors, trimmers etc?Martin
Does the carriage hit on something? Cables near the transformer, perhaps?
Transport safety screws losened?Martin
Which type of Beogram 4002?
Martin
The RCA sockets are known to break their solder joints.
They will have to be re-soldered.Martin
The broken tuning part is (was) merely a friction clutch.
Beomaster 1400 (M/K) was produced in the late 1960s, and since 1980 there were no more working clutches. They had all disintegrated due to the choice of material.
Luciky, the tuning will work fine none-the-less, – just without the flywheel effect.Martin
25 November 2023 at 12:07 in reply to: Beolab, Beovox Pentas – Ein Lautsprecher für die Ewigkeit #33994The OPA213… is end of life. No longer produced. Grab them while you can.
Or grab a kit containing them, that is pretty much based on the same upgrade theory.Martin
You could put a scope to the output of the tracking opto and follow the signal through the
electronics but, if your deck has not yet been restored with new capacitors etc., I think
that would be the place to start as more issues will almost certainly arise after this one has been fixed.Martin
Do you see light inside the shutter house at the foot of the carriage, when the deck is playing?
Martin
Note there are two types. One for each of the two tape drive versions.
Martin
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