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Old 13th Feb 2018, 2:54 pm   #1
vinrads
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Join Date: Feb 2009
Location: Chesterfield, Derbyshire, UK.
Posts: 3,738
Default Marantz 2230 tuner amp

Where to start. I do some repairs for this chap one day he came with a car full including the Marantz 2230 he didn't want to spend much on the repair, as one output stage had blown, it ended up being mine, quite a nice unit.

I sent to the USA for the 2SC897 output transistors he was selling five so I thought good plan in case I needed another pair not cheap but they were marked Toshiba, meanwhile the driver board was repaired checked and double checked, I didn't want to blow the expensive outputs. Some time later the transistors arrived they looked the part, so they were fitted with some trepidation I switched on, and was greeted with a loud pop , we now have four duff transistors, lights out door locked and

Next day repaired the driver board, I didn't want to risk another pair of the expensive output transistors what have I got that would fit found a couple of BU208A from my T/V repairing days, these were fitte , the big switch on no pop or bang or smoke, the idle current set perfect and it sounded good too .

Fast forward to this mourning tried the amp again perfect, so I will fit the proper transistors it will be fine, eer no it went with a big pop again, keep carm and carry on I thought repaired the driver board again fitted the two BU208A now playing away lovely .

The question were the transistors inferior they did test all ok Any thoughts please. Mick.

Last edited by vinrads; 13th Feb 2018 at 3:10 pm.
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