Hifonics zeus gen x

[Perry Babin]

Pin 4 doesn't have any supply voltage. Follow the circuit back to see what's feeding that pin.

 

[mike49504]

what should i be looking for i traced it to a diode and that was ok but after that i dont know what usually feed it

 

[Perry Babin]

I would think it would go back to a transistor but it could be fed from the remote turn-on:
Remote -> diode -> pin 4.

On many amps, the op-amps used for the protection circuits are fed by the same circuit as pin 12 of the 494 so you should follow the traces to/from pin 12 of the 494 to see if there are any open traces between that circuit and pin 4 of the 324.

Remember traces can be on either side of the board and can pass under other components. It's possible for traces to open under those components.

 

[mike49504]

damn i lifted if off the board and traced it back to a tip 102 that is testing shorted ill replace that and then check the voltage

 

[mike49504]

ok no luck still 0.66 on pin 4. But the problem with the tip 102 is whoever worked on this amp before me fixed a broken trace and soldered it to the wrong leg on the 102.

after the diode the trace from pin4 goes back to a cap so ill lift it off then trace it back from there

 

[mike49504]

ok i replaced another tip102 in the amp and i think it kicked on but after 4 secs it will draw 60 amps of current so if i take out the fes16jt's will this disable the outputs to see if the power supply will start up

 

[Perry Babin]

Removing the rectifiers should completely isolate the audio section.

Have you re-checked the output transistors to see if any were shorted?

 

[mike49504]

ok i disabled the audio section . amp doesnt draw alit of current now. but theres still a problem in the supply theres only .69 on pin 4 of the 324 so i guess ill try to track it down later today .

 

[mike49504]

ok i think i found what drives pin 4 its an a1266 wondering if this can be crossed to something so i can see if i can get this amp running or do i need the 1266

 

[Perry Babin]

What PNP transistors do you have on hand?

 

[mike49504]

ok i found an a1266 in a parts amp let me make a few solder connections and ill let you know what the voltage is on pin 4

 

[mike49504]

ok that didnt work still 0.69 on pin 4

theres an c2238 and an a968 wondering if theese cross to anything so i can see if theese are bad

and also theres an mpsa12 wondering in i can cross that also

 

[mike49504]

ok i think i might have found the problem .

Theres a chip in the amp that looks like a resistor pack the marking on it are as followed

prot4 revb zed audio 9706

This connects directly to pin 4

 

[Perry Babin]

Generally, those contain only resistors and diodes but I don't have the internal schematic for that particular one. You may be able to get it from ZED. While it's possible that that feeds pin 4 (if it has 12v on another pin of the network), it's more likely that both the 324 and the network are being fed from the same supply and that's why it's connected to the same trace as pin 4.

 

[mike49504]

Ok maybe that doesnt feed pin 4 sorry i was very tierd last night.
Theres the a968 and a c2238 and a mpsa12 that i need to check again but they were testing good. so i guss ill mess with this thing a lil more.

Is there anything i can cross the a968 and c2238 with??

 

[Perry Babin]

MCM has both of those in stock.

 

[mike49504]

Ok after unpluging by desoldering tip im gonna start tracing this circuit back again and ill let you know what i come up with

 

[mike49504]

Ok there is an a968 tied to pins 4 and 11 on the 324 wondering what voltage i should have on pin 4 of the 324

 

[Perry Babin]

Are you sure that the transistor is connected to both of those pins? Pin 4 is the positive power supply pin. Pin 11 is the ground pin.

I'd expect pin 4 to have ~12v on it if pin 11 was connected to ground.

 

[mike49504]

Ok pin 11 connects to the negative side of a cap pin 4 connects to the positive side of the cap following the circuit back there are 2 sets of a968's and c2238's in the circuit.

All of them seem to test fine but theres no voltage on pin 4 so i set my meter to diode check and checked the legs of theese and get nothing near 0

Is there a better way of checking them to make sure they are shorted or leaking