I just purchased a Nakamichi TA-2A Receiver / Amp. Now approaching 30 years old, I agree with the owner who suggests servicing. I know old caps can get funky, which puts everything at risk. But I'm no tech, other than decent assembly & testing skills. Are there any recommendations for what I should consider replacing / testing? I don't want to wait for a failure... Thanks in advance! (p.s... It's not even here yet, so I'm theorizing based on age alone. I did download the service / repair manual, so can test at various points - but looking for ideas on what to hunt for.)
Preventative maintenance would cover replacing any electrolytic caps whose failure might put other circuitry at risk (if you were being selective and not replacing all). A thorough visual inspection of the PCB looking for hotspots and cooked components and depending on the component type consider replacing. I would look at semiconductor types used in the power amp stages (drivers and VAS stage) and consider replacements on the basis that certain types of such Japanese devices can be inexplicably prone to failure. Replace any bias and offset presets but be sure you know how to set it up afterwards. And a very thorough check for dries, possibly reflowing all the joints on the PCB's as a precaution.
If ~1 Vrms and 96 kHz of abs max signal frequency are all that you need, such an integrated audio solution makes a decent AF SSG. You probably shouldn't be asking for THD <-80..-90 dB near maximum output, but often that'll do fine.
You don't generally need one for the amplifier portions though, as the manufacturer usually specifies an idle current range, and little more than a multimeter and maybe RCA shorting plugs (for the input) are required for offset adjustment. Adjustments in the receiver section are usally out of reach for mere mortals, getting the stereo decoder VCO back in line and maybe a slight discriminator tweak excepted.
BTW, do check bias trimpots for proper operation and clean them with suitable chemicals if necessary (or replace should they be falling apart). In some cases some movement and returning things into the old position may be sufficient.
You don't generally need one for the amplifier portions though, as the manufacturer usually specifies an idle current range, and little more than a multimeter and maybe RCA shorting plugs (for the input) are required for offset adjustment. Adjustments in the receiver section are usally out of reach for mere mortals, getting the stereo decoder VCO back in line and maybe a slight discriminator tweak excepted.
BTW, do check bias trimpots for proper operation and clean them with suitable chemicals if necessary (or replace should they be falling apart). In some cases some movement and returning things into the old position may be sufficient.
You can use Audacity to make your own test discs,
http://www.diyaudio.com/forums/soft...ing-using-audacity-get-you-started-guide.html
Bias and offset need no more than a DVM to check and adjust.
http://www.diyaudio.com/forums/soft...ing-using-audacity-get-you-started-guide.html
Bias and offset need no more than a DVM to check and adjust.
A dirty computer has started a fire at my previous place of work. Luckily it caught fire and not the office since we were there to put it out. Chucked the whole thing outside it smelled for days.
Maybe I've had good luck, but in most of the vintage equipment that I've seen, the main problem is dirty switches and potentiometers. Once those are clean and the heat sink wiped off, I'd burn in the unit for a few days. If there's a bias pot, that could be dirty as well. Often those are cheap and/or open construction, so I'd replace it if possible.
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