20241018 The Ending of Altec Lansing's ACS45.1

I do remember I used to have two Altec Lansing ACD45.1's but I could not recall what happened to the first one. And that was about, maybe, 23 years ago? At that time, these were going for RM255 at Computer Fairs and I loved it to bits.

I am not so sure about the history but at one point in time, Altec Lansing were going head to head with Cambridge Audio or something. The latter was quite expensive and thus, I got the ACS45.1 which was basically a pair of speakers with a nice subwoofer.

23 plus years later...

Or was it just 15 years or so? Anyway, this was my Second unit and it already did have some issues years before. To switch it on, you'd need to press the two volume buttons located on the top of the right speaker. That stopped working and so, I just powered it on from the mains. Then came the 'memory' issue where I had to re-adjust the volume everytime it powers up.

And well, lastly, just last week, it powered up and then the green LED sort of fizzled a little and then faded off. The Internet suggested that I replace the inferior TP2256 chip with the Toshiba's more robust TC9235P since it was the source of most problems.

 The TC9235P

 

Inside the circuit board is the crucial Volume Control IC called the PT2256. From the Internet, it was touted to be the more cost effective version of Toshiba's more robust TC9235P. Both chips are pin for pin compatible. And therefore, I decided to get two.

Surprisingly, it came in record time. The Seller packed it quite well, even for just tow IC chips.

The Main circuit and amplifier lies in the subwoofer enclosure of the ACS45.1 The whole enclosure is made of wood. The circuitry and port is held with 8 screws.

That is quite a big heatsink...

Not shown here, but inside is the big transformer.

Found the PT2256 chip

The de-soldered PT2256 (bottom) and the new TC9235P ICs.

I used a lot of solder flux as I want to clean the soldering and also, to make sure the new solder flows into the PCB as fast as possible. This is because the PCB is brittle SRBP and not those FR4 fibreglass which are so common nowadays. See the small SMD resistor '392'? It is not leaking but I suspect, is glue to make sure the component does not move about during wave soldering, I think.

After cleaning with IPA, the board looks good to go.

Finally...

Once everyting is cleaned up and the board fastened back in, it is time to test the repair. And as expected, the green LED glow into life when powered on and it... fizzled and died.

Sheesh.