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chilledspode
04-03-2017, 04:58 PM
I originally posted over in the pro amp section but in retrospect, this is more accurately a consumer amp.
I have a fine tech beating his way through a trial and error process trying to create a new transformer to power the front panel backlighting and I would sure like to help find some specs for him to work from.
Would anyone happen to have any intel/gems that might be of use to him?
Thanks folks
Mark
nb: The Crown service manuals apparently don't provide much info on this particular component

hjames
04-03-2017, 07:18 PM
Apparently we are missing a chunk of the conversation -
why can't you just get a replacement transformer from Crown?
why would you have to re-engineer one/Create a new one for a backlighting circuit?

No, I am not trying to be snarky at all, honestly, I'm just not getting the plan ...

chilledspode
04-04-2017, 07:16 AM
Thanks for asking and no offence taken :-)
Crown no longer supplies parts for this amp of roughly 1992 vintage.
Given the long history between Crwon and JBL, I was hoping someone here had experience restoring these amps.
Cheers
Mark

chilledspode
04-04-2017, 07:24 AM
This the amp and the backlighting is apparently some sort of electroluminescent (EL in Crown speak) that my tech describes as being driven by a high speed switching transformer of unknown voltage.
Here is unit
Mark
http://img.canuckaudiomart.com/uploads/large/1010767-crown-macro-reference-esoteric.jpg

Ruediger
04-22-2017, 01:07 PM
The component seems to be a DC/DC converter. That is meant to be a "black box", you don't need to care about the internals. It contains some high speed switching circuitry with a tiny transformer (core plus some windings), but that is - see above - "black box", and it cannot be serviced (repaired).

Try to determine the specs of that DC/DC converter, and get a spare for the whole converter, forget about the "transformer".

The converter appears at the bottom of schematics page 2 of 3 (named EL Power Supply) and at the left of the pcb in service manual 8-2-22.

Google for "DC/DC Converter" and have a look at the pictures. That should look familiar.

Ruediger

Ruediger
04-23-2017, 12:44 PM
I was wrong when I thought the component was a DC/DC converter. It is a DC/AC converter.

Manufacturers of EL foil supply the converter together with the foil, and you can buy the converters separately, for example "12 volt electroluminescent inverter for EL ..."

Still it remains a black box, not serviceable.

Ruediger

chilledspode
10-29-2017, 07:19 PM
I was wrong when I thought the component was a DC/DC converter. It is a DC/AC converter.

Manufacturers of EL foil supply the converter together with the foil, and you can buy the converters separately, for example "12 volt electroluminescent inverter for EL ..."

Still it remains a black box, not serviceable.

Ruediger

Been awhile but I wanted to provide an update.
As you stated, EL folks sell transformers with their product and we managed to replace all the 'ghastly' green films and it looks as it should.
Now have a bad CH 2 that needs to be sorted - the long weird journey continues.
Thank you for your time and input.
Cheers
Mark