Macro-tech 5000vz

[plec.22]

I've got one of these old monsters in for repair, it's fault is, power's up but straight in to protection mode with orange leds on...also it's inrush thermistors are both over heated and o/c so fitted replacements.
The thing is the old ones are gray but new ones that where recommended are blue but smaller in size.. anyhow it's service info say's it's holding it self in stand by mode to stop damage plus there is fault led's within the rear panel to show possible indication where the faults lay..such as dc on o/p etc. It was also left on 24/7 in a rack till someone noticed part of the system was down...

[Jazz P Bass]

A very complicated & sophisticated amplifier.
http://www.crownaudio.com/media/pdf/legacy/103169.pdf

[km6xz]

Are you seeing the ODEP indicators are glowing amber? That is the normal condition and the go out when exceeding reserve capacity.
What are the all the lights doing with no signal, and then with a signal? Which lights are showing red protect mode?

[plec.22]

At power up you can hear the fans run with thud from the inrush because the ptc thermistors are o/c followed by bright signal leds on.. so powered off the amp, I was going to slowly bring up the voltage using my variac and look to the rear panel leds to see fault indication as per service book..

[plec.22]

I've got the schematic so began looking over that so the next plan was to remove the 20 amp fuse to one channel and work one block at a time.

[Jazz P Bass]

It may be best to 'start' at the output module cassettes.
Most probably you have a blown channel.
The high voltage relays will not kick in until you remove the fault.
The fault LEDs on the main board are as follows.
Crown 5000VZ Fault LEDs.doc

[Jazz P Bass]

At power up you can hear the fans run with thud from the inrush because the ptc thermistors are o/c followed by bright signal leds on.. so powered off the amp, I was going to slowly bring up the voltage using my variac and look to the rear panel leds to see fault indication as per service book..

When the fans are running a winding on the fan provides the low voltage power supply.
You may want to check each channels bridge rectifier.

[plec.22]

Will have a look on the o/p cards and test each transistor out of circuit for short circuit as both leds on front panel stay bright orange followed by any damaged parts etc.

[Jazz P Bass]

For now you only need to see if the outputs are shorted or not.
Yes or No.
There really is no need to remove all of the transistors, until you find a shorted cassette.
The idea here is to narrow down WHY the amp is in protect.
There are a number of things that can keep it from coming on.

[plec.22]

no s/c o/ps and all of them are ok to both modules.. plus replacements ptc's fitted due to them being damaged..