identifying capacitor type

[snk]

Hi,
Thank you for the help.

I measured the resistance across the main plug with the power switch on, and i got around 72ohm (which seems fine according to the figures you gave above).

Here are some pictures of the transformer : the cables are wired in such a way that I don't know what I can do with it (I mean : I don't know which cable goes where, and I only can reach shielded/coated parts of the wires, the transformer pins are all inside).

[Ice-9]

I have not read all the replies and it may have been answered earlier.
1. the yellowish looking caps are electrolytic capacitors and the grey one is most likely a Polyester capacitor.

[Rob Strand]

I measured the resistance across the main plug with the power switch on, and i got around 72ohm (which seems fine according to the figures you gave above).

The main point is you are getting a reading, and a reading which is very much in the ball-park of what you would expect.   

FWIW: I'm pretty sure the transformer is rated somewhat higher than 20VA.   A rough guess 30VA and  it could be upto 40VA based on 72 ohm and it being an early 60s design (large in size compared to modern hot transformers).   

The next step would be to start checking the secondary voltages AC and then DC voltages.   At some point you might find the supply is lost.   You then need to debug it.  Perhaps a bad connection, burnt part, burnt resistor.

Just a friendly warning, watch out when poking around in those older pieces of equipment.   There is often plenty of places with *exposed* mains wiring.   It can be all through the unit: Switches, fuse holders, terminal strips  not the mention the voltage selector.    Perhaps even some exposed mains caps.   If you aren't used to poking around with mains power stuff it might not be obvious what parts are actually main wiring.     Experienced people can see this stuff straight away.   If you can, try to trace the mains wiring from the power inlet through the switch, fuse, voltage selector then to the transformer.   You don't need to mess with this wiring it's just good to know where the mains is so you don't accidentally knock or touch it.   


Another thing to be aware of is tape units often have switches activated by the mechanical buttons or mechanical parts of the tape mechanism.   If one of those is damaged or misaligned it might not turn something on.

I don't know if the unit is like that.   A schematic would highlight any power switching.

[snk]

Perhaps a bad connection, burnt part, burnt resistor.

Talking about bad connection...
This wire goes from the transformer to the circuit board
.

I think it would be wise to remove the screws and check the transformer for a closer inspection (by that, I mean being able to check the wires and solders).

[snk]

... Ok, so I just pulled slightly the green sheath protecting the wires, and... the wires just turned to dust 
At least two of them were already cut, a couple others were green inside (oxyde, I guess), falling apart and breaking at the first occasion.
This is not surprise then that the unit didn't work, and it could have been harmful to try to plug the transformer once again I guess.

I need to :
- remove the green sheath, open the transformer to get access to the wiring pins...
- ... and change every wire! The main issue will be to know for sure which wire goes where, as there are two white ones, two brown ones... and they are cut, split, sliced 

Another thing to be aware of is tape units often have switches activated by the mechanical buttons or mechanical parts of the tape mechanism.   If one of those is damaged or misaligned it might not turn something on.
I don't know if the unit is like that.   A schematic would highlight any power switching.

I don't think there are such switches on this model.
I have put a link to a schematic in the first post, I'll include the schematic here for reference. It is the schematic to the bigger unit (with a vumeter and HP/LP filters), but except from that I think the units are similar (and I think it's the only schematic available). On my unit, I see that the inner chassis has some holes (to put the vumeter), and one circuit board also features holes for the filters (cf. picture some posts above).

[Rob Strand]

... Ok, so I just pulled slightly the green sheath protecting the wires, and... the wires just turned to dust 
At least two of them were already cut, a couple others were green inside (oxyde, I guess), falling apart and breaking at the first occasion.
This is not surprise then that the unit didn't work, and it could have been harmful to try to plug the transformer once again I guess.

Wow    

I'm assuming that's PVC wire.    It decomposes and corrodes the wires inside.   Usually smells while it's doing it but yours has gone crispy and probably only has a slight smell.    I've only seen a few cases but that is the most severe I've ever seen.   (Rubber sheath corroding from that era is very common.)

Yes, it's not safe as is.  Might take a bit of time cleaning all that up, however, with any luck the wires are the only problem.

[pacealot]

I believe it's an endemic issue common to '60s Italian-made echo units — I once had a Binson Echorec carcass, the wiring of which was in a similarly advanced state of self-destruction....

[snk]

Yesterday, I removed the green plastic braid surrounding the cables 


Now I need to open the transformer to reach the pins, and change all the cables.

[kaycee]

You probably already know this, but just in case. These units are highly prized by Hank Marvin/Shadows fans, so there are probably small groups out there dedicated to repairing these if you haven't already looked.

I vaguely remember following someone making a 'modern' analogue version of one of these in a much smaller unit, without the tape drive etc I think. This was several years ago though.

Good luck getting it going, nice piece of history there.

[snk]

Hello,
I know tape delays are sought after, and I do indeed love them, but I wasn't aware about that Meazzi cult (in fact, I barely anything about the Shadows)
It's a quite bulky and heavy unit, so I am not considering shipping it to a repairman yet. If I fail to service it, I know someone who may know how to fix it.
In any case, I'll let you know how things go

[snk]

Well, this thread as gone away from the initial topic (identifying capacitor), but I think it's interesting nonetheless

Sadly, I think I'm stuck with the transformer : the wires go inside some thick cardboard (?) with holes, so I can't reach the transformer pins to solder new wires to it...
I removed the first "iron belt" holding the transformer to the chassis, but there is a second "copper belt" keeping everything together (including the "covers"), and which can't seem to be removed without being desoldered (which I think is unwise).
There is no label, no brand, no model number on the transformer to identify it...

Would anyone know how to reach the transformer pins (so I can remove the old wires and solder new wires)?

[PRR]

The copper shield will unsolder readily. That's probably the least of your problems.

[snk]

Thank you, Paul.
by that, do mainly mean that it will be easy to reach the transformer pins, or that I may encounter many more bigger problems?

[PRR]

As Rob has said, I think the further in you go the more rot and corruption you will find.

I do think you should hook-up with the fan-club before you go deeper.

[snk]

I do think you should hook-up with the fan-club before you go deeper.

Ah ah! I get you : that may be wise indeed

[Rob Strand]

I do think you should hook-up with the fan-club before you go deeper.

Ah ah! I get you : that may be wise indeed

They probably have a lot of good tips on handling the mess.

That transformer looks tough.   Best case scenario would be remove the shield and solder new wires.   However it's an overwound transformer with a phenolic bobbin and it's probably got paper insulation.   You might need to tread very carefully with it.