Ohhh Mighty Broadcast Gods... I need your help again. Yeap, the Stereo Gatesway

[SFM-Ptgal]

Now I really scr**d something on my Stereo Gatesway...
There were a few mods made from the previous owner station. One of them were two relays installed for channel 1 and 2. They've a common power source (parallel fed) . So I took the loose power cable (?) wich once fed them and connected a 9v battery to it and the result was that the console's original relays clicked. The added one's no.
Now the stupid thing: I dropped the cable inside the console and it touched the metal screens of the inside cables. It made a spark.

Now the result:
B4 the accident when I connected the console the 3 original relays clicked 1-2-3... When I disconnected they "de-clicked".
After the accident I can only hear one relay clicking. The relays are conneted to a pcb with 3 transistors and the rest are resistances.

Perhaps a burned transistor?... At least?...

Thank you for your help and patience

 

[amfmsw]

In the 70's I had a TV/Hi-Fi repair shop. Your journey with this thing reminds me of working on tube Magnavox Color TV consoles and, god-forbid, Entertainment Centers. Proudly Union made in Fort Wayne, Indianna, they would work for eternity if you never turned them on or off. Once something failed, and you needed to remove the back, it was a pandora's box of evils. The PC boards were aways crispy from tubes, boards being too large and poor ventilation. Disturb just ONE little thing to repair/replace it, four other things went bad!

You sir, have got a Magnavox.

 

[jboydingram]

Pls refer to my earlier post where it was recommended that you stay "external" from this device...now you, perhaps, get the message...Good Luck...JBI

 

[K4WRF]

It is indeed commendable and “a wise man, is a man who seeks council”. Turn to the all knowing Gatesway instruction manual, read and understand “theory of operation” then follow schematic and see the error of your ways. Enlightenment awaits….

 

[Tom Wells]

The spark was truly overcurrent on one of the three transistors.

Magnavox was often called maggotbox for the can-of-worms engineering.

Anything can be fixed. I would pull each transistor and check junctions on each.

You maY be able to add resistances or at least fuses in the emitter lead of each transistor to prevent recurrances.
As long as the relays will still pick up.
You may be able to find a transistor with the same Beta which will deliver more current perhaps even enough to laugh at such shorts,
getting hot but not croaking.

 

[SFM-Ptgal]

Yeap... Transistors 1 and 3 and their diodes on the relay and muting driver pcb are dead. I measured the tensions and the one's related to that transistors are null.

Now I really need to get a decent tip for my JBC iron...

Thanks for you patiente!

P.S.- Hey JBI! I understood your advice right from the first moment. But there are things that must be done, some not and some carefuly done , this last was my fault yesterday...

 

[Robert Bass]

P.S.- Hey JBI! I understood your advice right from the first moment. But there are things that must be done, some not and some carefuly done , this last was my fault yesterday...

It's a dirty job, but someone's gotta do it, eh? Maybe Mike Rowe can help you with this. ;D

Good luck!

R

 

[SFM-Ptgal]

P.S.- Hey JBI! I understood your advice right from the first moment. But there are things that must be done, some not and some carefuly done , this last was my fault yesterday...

It's a dirty job, but someone's gotta do it, eh? Maybe Mike Rowe can help you with this. ;D

Good luck!

R

Well, I think I traced the problem. I forgot to take note of the needed transistors and diodes before leaving home to work. Now I'm able to buy them just next Monday.
Does anyone around have their codes? It's on the relay and muting driver pcb diagram of the Stereo Gatesway 80 console :-[ If I get them on useful time I might go to the radio shack and buy them today.