9090DB Protection Red "Ready Green" Light

Duke

Active Member
Hello,

Just took delivery of a 9090DB - and should have bought one years ago . . .

Everything seems to work, sounds good, a bulb or two might need to be replaced.

So, here's the ?: When I power it on, the red protection light fluters for a few seconds which is normal, then the unit powers on fine, but the ready green light does not illuminate?

I am told this a LED, which if the Red light works the Green one should work as well - any suggestions of how I might get the Green light to work as well?

All comments and suggestions are "greatly" appreciated.

:dunno:
 
Be happy cuz usually the green light not coming on and the red staying on means the protection relays are not engaging for whatever reason and you get no sound. Since you have sound I would just say the green LED is out.
 
no green light

This is the only fault that my 9090db suffers from.

On power up the red protection light flashes 17-18 times and then the relay closes but the green light I have never seen.

I figured that if/when the red light goes out, then I will replace the green also.

I think the only way to get it to work will be to replace it as i don't think this lamp is prone to the oxidation of the contacts like the dial lamps.
I guess there is probably some wiring off of the relay that powers the green light but wouldn't suspect that would be the problem.

It never bothered me enough to investigate the matter further but if you do please keep me posted.

Thanks,
Tal
 
As I said you both should be very, very thankful, I had a G-7700 and when I got it home the red stayed on, no green and no sound :mad: Had to take it to the repair shop.
 
I am Very, Very happy in all aspects with my 9090db from it's performance, it's looks and particularily it's price..
Best Damn $6.99 I EVER spent!
Tal
 
Are you saying the Red light quits flashing but the green does not come on? If so probably R12 on the protection board is bad. The "light" is a dual LED they usally never go bad but the resistor on the protection board does.

R12 1.5K 1/4 Watt, I would replace with a 1/2 Watt.
 
R12

Thanks for the tip.
In fact I have to drop by my local electronics supply this afternoon.
I may just pick up a resistor with that value just to try it out.
Thanks,
Tal
 
Just a not it is a pain in the A-- to get to, you have to remove the tuner and the bottom to get to the resistor. Do you have a diagram of the Protection board if not I will send you one.
 
No I do NOT have a diagram.
I will be leaving here an a few (only have email at work and only work M-F) but my email is :
forquermt@billings.k12.mt.us

Thanks,
Tal
Guess I should have said no hurry, i'm not to rushed to fix it but certainly would like the knowledge to be able to fix it
 
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I think this topic came up not too long ago in the Archived messages. I have the same thing on my 9090DB, no green. Otherwise, its an near-pristine condition. I just havent had the time to go thru the whole effort to get at the resistor to replace it in order to have the green illuminating again.

B/F
 
These protection circuits are not fool proof. I have seen relays engage with shorted outputs and certain faults when it should not be possible. Defective circuits and poor design can affect any part of the unit and just about anything is possible. Murphy's law - Anything that can go wrong usually does.
 
I think that the resistor is too small for the job that it is doing. I have had three with the same problem R12 open. Indicates that the overhead on the wattage was to small, all the resistors were open but not burned.

Major Pain:dammit:
 
Originally posted by RocknRoll
These protection circuits are not fool proof. I have seen relays engage with shorted outputs and certain faults when it should not be possible. Defective circuits and poor design can affect any part of the unit and just about anything is possible. Murphy's law - Anything that can go wrong usually does.

On the 8080DB/9090DB on most of the units there were fuses on the protection relay board. On the later models they replaced them with jumpers. I'll bet they had a bunch of units blowing the fuses and having to replace them. However, with out the fuses the protection relay can fuse together and and smoke your speakers if it does react quick enough.

I replace the jumpers with fuses on all the ones that I work on. just a safe practice.
 
I think those 10 amp fuses in the 9090DB PSU are too high. If you look at a 9090 they are 6 amp fuses! 15 Watts less per channel but 10 amps is alot of current.
 
All the ones I have seen have 7 Amp fuses, which is what is the service manual calls for. Don't mistake these for the ones on the power supply board which are 10 Amp.
 
In both cases on the power supply board on the secondary side of transformer and not the main Primary side fuse. I have no idea why the 9090db is 10 amp fast blow when 8 amp seems to be safer. On my 9090 it is 6 amp (printed right on the board) and main fuse is 10 amp slow blow (printed above fuse holder)
 
I'm not sure, the 8080DB is fused at 7A on the secondary and primary of the transformer. It is an 85W unit.

That being said, he only time I have seen these fuses blow is when one of the output transistors shorts. In that case a 20 Amp fuse would probably blow.
 
EW here on Dingus's computer..... (since the forum rework, the cookie clearing thing doesn't work...so I'm posting on his account. Brad being the postwhore that he is, I doubt he'll mind...)

Me replacing a 1.5K 1/4W resistor in a 9090db with a 1.5K 1/2W resistor for....the green LED, of course.

Note that I'm so damn good that I work with my eyes closed...;)
 
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