Revox A77 Tape stop lamp

[stevehertz]

I posted some time ago (years) re how the spool on my A77 kept running after re-spooling etc. I have finally got around to checking things out. The tape stop lamp was O/C. Bought a new one, fitted it, it doesn't illuminate. Under what conditions; tape presence, buttons, switches etc should the lamp be illuminated? I'm thinking it should always be on when the machine is powered up? Does the sensor 'have a say' in whether the lamp is illuminated? I have read that the sensors can play up either truly faulty or a change in parameters.

Previously (after the tape stop problem) the machine went bang when I switched it on. The four suppressors were all split and I have just replaced them with proper ones from a Revox supplier. Maybe the supply to the lamp is down? Otherwise, although I have not dropped a tape on to the machine yet, the spools all act as I would expect them to on FFWD, FREV and PLAY (back tension there etc).

[ms660]

According to the schematic I'm looking at, the lamp should be permanently connected via a connector to the 21 Volt supply which is fused and regulated, normally it should illuminate when power is applied to the machine and it's switched on.

Lawrence.

[Restoration73]

As said check the socket. Note the wedge bulb is available in two types, 1000 hour life
and 10000 hour - price is similar.

[DMcMahon]

Originally Posted by stevehertz

I posted some time ago (years) re how the spool on my A77 kept running after re-spooling etc.

This one most likely:-

https://www.google.com/url?client=in...gSR7mCn_mrKNJt.


David

[stevehertz]

Thanks guys I'll check that 21v supply out.

[KeithsTV]

I've had the stop lamp appear to have failed but it was the ground lead from the bulb holder making intermittent contact with the chassis.

Keith

[Analogue man]

Normally if the 21v supply is faulty the machine will not play or wind unless you hold the buttons in so I think that the supply is probably ok. I'd be looking for a wire off somewhere between the PSU and the lamp.

[TIMTAPE]

I've found the terminals in the socket can oxidise over time. For long life an LED with suitable current limiting resistor can be soldered in. The later B77 and PR99 had an LED.

[stevehertz]

Tim, given how tight the lamp fits, I'd doubt that the socket's contacts are causing the problem, nonetheless I'll check that out. As, regrettably, I'll be selling the deck, I am happy to fit a stock part as a replacement.

[stevehertz]

Ok, just had another go at it. TIMTAPE you are quite correct - thank you! I 'rubbed' the socket contacts with a jeweller's screwdriver followed by a squirt of Servisol and hey presto, the lamp illuminates.

Now a full check over before sadly offering it up for sale.

[TIMTAPE]

Originally Posted by stevehertz

Ok, just had another go at it. TIMTAPE you are quite correct - thank you! I 'rubbed' the socket contacts with a jeweller's screwdriver followed by a squirt of Servisol and hey presto, the lamp illuminates.

You're welcome.