Hey all,
I decided to play around with my amplifier - Sony TA-242, refresh any suspected cold joints, replace few electrolytic caps etc.
I was also planning to install Little Bear P8 valve pre-amp and headphone amplifier between input and source selector I thought it might give it a bit of "tube-like" sound + II would have nice built in headphone amp.
To cut story short after redoing few joints and replacing 5 or 6 small caps I've connected the amp and heard loud pop and then constant humming. Disconnected from mains quickly and checked what is being delivered to speaker terminals - ~23V DC :/
I suspect that I have fried STK460, which I could replace no probs, but just wondering about one thing.
I have de-soldered STK chip and checked voltages on output. I was still getting between 2-4V DC. Is this normal without chip installed and or speakers and source connected? Should I try and get another STK460 (or 459 or 461) and just pop it in or should I do some more testing? If so where should I start?
Many thanks.
I decided to play around with my amplifier - Sony TA-242, refresh any suspected cold joints, replace few electrolytic caps etc.
I was also planning to install Little Bear P8 valve pre-amp and headphone amplifier between input and source selector I thought it might give it a bit of "tube-like" sound + II would have nice built in headphone amp.
To cut story short after redoing few joints and replacing 5 or 6 small caps I've connected the amp and heard loud pop and then constant humming. Disconnected from mains quickly and checked what is being delivered to speaker terminals - ~23V DC :/
I suspect that I have fried STK460, which I could replace no probs, but just wondering about one thing.
I have de-soldered STK chip and checked voltages on output. I was still getting between 2-4V DC. Is this normal without chip installed and or speakers and source connected? Should I try and get another STK460 (or 459 or 461) and just pop it in or should I do some more testing? If so where should I start?
Many thanks.
Try and locate the reason why it failed in the first place... you have obviously done something amiss.
Replace the STK with one of the same type, and use a bulb tester for initial powering up after you have replaced it.
(it is probably normal to see some voltage without the STK fitted)
Replace the STK with one of the same type, and use a bulb tester for initial powering up after you have replaced it.
(it is probably normal to see some voltage without the STK fitted)
The STK chips are very reliable so I would check for short circuit solder lands, too much solder, incorrectly/wrong value electrolytics fitted etc first.
The voltage you measured without the output chip fitted is normal.
The voltage you measured without the output chip fitted is normal.
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