Help with hafler mse40

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Hi, im new to this forum, but have been following it for quite a while. It may be a shot in the dark but i was hoping that someone could help me in repairing my hafler mse40si car amp. I bought it very cheap, and knew that it was broken.

When i hook it all up to my workstation the only thing i get is a huge amount of distortion through both channels. You can vaguely make out the sound of music in there, but only the beat really. I change out all capacitors to no avail. Also, when i got it the gain knobs were falling off so i replaced them with what i think is the right value gain pots, even though they are too big and i probably need to replace them with something that fits better.

The board looks fine, with no burns, or spilled electrolytics as far as i can tell.

I was thinking about replacing the transistors, but before i tackle that i was hoping that someone that knows more than me could tell me if they think this is the right path.

If somebody could help me out it would be greatly appreciated. If pics will help i can get them too. I have had no luck getting any schematics yet.

Thanks a lot, Chris
Here it is. I think its supposed to be similar to the punch 45. But better sounding. Ha


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Yup that is a Rockford Fosgate-Hafler amp. And the likley culprit for distorted sound is those rectangular black IC channels driver chips, one for each channel located toward the upper section of the PC board, across from the RCAs. Those are custom Rockford Fosgate devices and only available thru them as I recall.

The amp looks to be in fair shape. I would verify the power supply is operating correctly < I.E. make sure all the voltages are correct and stable >. And then ohm out the output fets to verify they are OK < they are clamped to the wall between the RCAs and the speaker wires >.
If all that checks out then your likley looking at replacing those rectangular ICs. I have seen them fail enough over the years that those are my main suspect. They are only available from Rockford to my knowledge, but that was back in the early 90's when I bought my last one from them. Perhaps someone here knows of a replacement device that I am unaware of ...

These are relatively simple amps by design, so there just is not too much else that could go wrong with them.
hey guys. i finally got in touch with rockford about this. the guy i keep talking to doesnt seem to know much about anything i asked him, including the ic chips that 1moreamp mentioned. he said that they are NOT proprietary Fosgate chips... but like i said, im not sure if he knows what he is talking about. he also said that my best bet would be to look on mouser or something like that. im going to post the schematics in hopes that someone can point me in the right direction to where i can find these parts. maybe hes right. the chip on the schematic is called a CA225 SS-733c. it has 28 pins. does this ring a bell with anyone?
Like you said he doesn't know much about I will disagree with your Rockford source those are custom house number chips just for Rockford / Hafler amps. Guess your Rockford source was in kindergarten at that time, after all it was 20 years ago.

I do wish you luck in finding some NOS inventory somewhere, perhaps a offshore Rockford service center like in Canada or Europe, or the east coast. 20 year old car amps using custom parts like RF used can be impossible to repair because of this issue. They designed in guarantied obsolescence due to lack of factory of luck...:)
awesome man. yea the guy sounded real young.

that would be a great help. i could pay you for them for sure. thing is, i think i need 2 of them.
i actually just found some brand new boards for this amp and bought a couple for 12 bux a piece on ebay. would love to get my hands on about six of those chips. was thinking about building some from the ground up. i wish they used tl074's like every other old amp i have.
I will find the part number for you, and if I cant I have at least 50 of these chips from new and used boards I could remove one and send it to you just to get you going.

Thank you seankane for coming to the rescue. I never collected any of these after RF got hold of the Hafler name, fixed a many but I never kept any hulkers of these. Let me know if you can salvage four more pieces I have another DIY friend that needs them for a mse-88... ;) < I sent a linky to my friend in need so he might contact you directly..

Drumcrusher be aware these ICs are fairly static sensitive. they came from RF wrapped in aluminum foil when I got them, and I had a couple failures just installing them most likely due to static issues.. again best of luck on the project...:)
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I didn't collect many either. They were great sounding amps but just was never that into them.

I have several Hafler amps I will be getting rid of soon. Don't need them, maybe they could be used for parts and such.

I really have not got a chance to work on many, I just don't see many around.

I have 3 or 4 120di 6 channel boards and each of those boards have 6 of the chips.

I would be happy to help out.
Well I had my guy who works at Rockford dig through the old archives and he found a schematic with a bill of materials attached for the MSE120di.

The 120 and the 40 use the same IC's.

The part number that the bill of material gives is just CA225. That's almost impossible to cross.

I have boards here with the chips on them, but there is no way to tell which ones are good and which ones are not. Its a gamble I guess. Some of these boards are new never used. That does not mean they are good though.

I have attached a copy of the MSE120 schematic so you can see the part number.


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Thanks seankane, Message has been sent to my friend about your kindness and offers.

House labeled and custom packaged ICs pretty much like everything Rockford built during those years < taking into account the HD product line and all of its pre-assembled ceramic modules>.

When they were doing that they had moved to Mexico for assembly of most of their amp products as I recall so I am guessing the engineering of ICs and modules were done to stream line the assembly line and to protect their proprietary product designs, and to allow for untrained assembly staffing since they were moved to a place electronics assembly at that time was foreign to.....Just business as normal in my mind. I would have considered doing these things back then what with the move and all, plus economics of the day back then..

Thanks again for your help seankane :)
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Hey guys first post. I am just getting back into car audio again putting a system in my honda. I have 2 Hafler amps I have been keeping and would like to use for this setup but i would love to get the manuals if i could, please. If any one has them kicking around and could scan them up for me it would be greatly appreciated.

Thank You,
Long live the dead thread, sorry bout that.
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