1G Orion HCCA 225

[jkrokenberger]

I have 2 of the first gen HCCA 225's here. One has had no repairs other than me replacing the large 3300uf cap on the power input. The second has been molested, not badly but some.

What are the proper rail voltages for these things? The unmolested one is much lower than the repaired one. Both are Rev. G boards. Both power up and have almost zero DC offset.

The repaired one pulls down my 4A power supply much more than the untouched one. Idle current is 300mA on the good one and 2.4A on the repaired one. Both idle.


Unrepaired one has +-18v rails.
Repaired one has +-26.5 rails.

Something seems amiss.

Jason

 

[jkrokenberger]

The added current seems to be the to220 transistor that controls the switches. It gets hot FAST. It appears to have been replaced, as well as the 2 small transistors in the Psupply. 2 of the Psupply switching transistors have been replaced but none of them get warm like the one on the end by the speaker/remote connector.

Jason

 

[Perry Babin]

Are all of the parts that have been replaced the correct parts, installed correctly?

 

[jkrokenberger]

I'm not sure. I cannot ID the transistor that is getting hot, it has been replaced. I can see one of the diodes by it has been replaced and the 2 small transistors in the PS as well. Do you know the correct parts?

 

[Perry Babin]

All of the PS switchers and that one are 2N6488s.

I think the two small transistors are MPSA06s.

What is the number on the Zener indicated in the attached photo?

 

[jkrokenberger]

I will be reporting back.


Jason

 

[jkrokenberger]

The zener with the arrow is original. The one to the right of it has been changed. The 2 small transistors are NTE 287 parts. Should I put a new rack of 2N6488s in the PS once I get it proper? I know they aren't matched any more.


Jason

 

[Perry Babin]

The number is important because it determines the rail voltage.

 

[jkrokenberger]

(Motorola logo)K
1N
47
46
415

Numbered like that on the body. I pulled it from the board to get numbers. The legs were blackened by the body. Could it being bad cause the symptoms the amplifier is having?

Jason

 

[Perry Babin]

You should have ±18v (approximately) for rail voltage.

With the diode in the circuit, what voltage do you read across it?

 

[jkrokenberger]

I have the board out of the sink and fear the one transistor will burn up. Should I just replace the diode as it looks to have gone bad visually?


Jason

 

[Perry Babin]

Just power it up for a second to measure the voltage. If you have to, set it back in the sink and install the two screws holding that transistor down.

 

[jkrokenberger]

Will do sir. I have ordered diodes and PS transistors for it so they all match. I will replace the diode and transistors, measure and report back.

Jason

 

[jkrokenberger]

I've replaced the 18v zener with a new one. I get 18.3v across it. The amplifier is also staying powered when you remove power from the remote lead.



I have a better camera now too.

Jason

 

[Perry Babin]

Confirm that there is 0v on the remote wire when it's disconnected.

IS the LED just lit due to charged caps or is the power supply still in full operation?

 

[jkrokenberger]

Still in operation.

 

[Perry Babin]

Confirm that there is 0v on the remote wire when it's disconnected.

 

[jkrokenberger]

The longer the amp is powered up the more it goes negative of ground.


Jason

 

[Perry Babin]

What's going more negative? You need to be precise/specific.

 

[jkrokenberger]

I am sorry. The the longer the amp is powered after the initial 12v to the remote wire and removed the further below negative the voltage on the remote lead goes. It will start at 0v once the +12v is removed and drop to -1v after about 5 mins and goes further negative the longer it's powered up. The power supply remains in operation at ~+-28v rails and I have 18.3v across the zener you had me check and I replaced.


Jason