Im servicing an original 'heater' version D200 amp here, with TIP35 BJTs in the PS and TIP141/TIP146 output darlingtons.
The 'outer' PS had several failed components including almost ALL 1n914 diodes, a 15v cap, and an MPSA92. Replaced all. TIP35 are OK.
The 'inner' PS had two failed 1n914 diodes and a failed MPSA92. Replaced all. TIP35 are OK.
On the amp side,
The 'outer' channel also has a failed TIP146 which I've removed for now.
The amps and PS are connected as such.
'Outer' PS is connected to the 'inner' amp (Marked in YELLOW in the below photo)
'Inner' PS is connected to the 'outer' amp.
Fully powered and only minus the failed TIP146, the amp idles at about 2.3A. The problem I'm seeing though, is the 'outer' ps is only producing +-36vDC rail, while the 'inner' ps is producing +-46vDC. Thats quite a significant difference from channel to channel imo.
Any thoughts as to why such a difference with this amp?
Photo next post.
The 'outer' PS had several failed components including almost ALL 1n914 diodes, a 15v cap, and an MPSA92. Replaced all. TIP35 are OK.
The 'inner' PS had two failed 1n914 diodes and a failed MPSA92. Replaced all. TIP35 are OK.
On the amp side,
The 'outer' channel also has a failed TIP146 which I've removed for now.
The amps and PS are connected as such.
'Outer' PS is connected to the 'inner' amp (Marked in YELLOW in the below photo)
'Inner' PS is connected to the 'outer' amp.
Fully powered and only minus the failed TIP146, the amp idles at about 2.3A. The problem I'm seeing though, is the 'outer' ps is only producing +-36vDC rail, while the 'inner' ps is producing +-46vDC. Thats quite a significant difference from channel to channel imo.
Any thoughts as to why such a difference with this amp?
Photo next post.
Also just checking on if TIP147 in a TO-3P package would be a good sub for the obsolete TIP146 TO218?
Or I can fetch what looks to be OE original ST/Morocco TO-218 TIP146 from eBay for about $11 per unit...
Or I can fetch what looks to be OE original ST/Morocco TO-218 TIP146 from eBay for about $11 per unit...
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Check the TIP31 (Q12) in the power supply with the higher voltage. It is part of the regulation circuit.
Thanks. All TIP31 are testing OK.
It seems this amp is in dire need of new CAPs, possibly at higher rated voltages. All caps in the PS which is running close to 90vDC rail are only rated for 25v & 35v. AND they're getting quite warm, especially C6 - its getting hotter than I can touch. Also in the lower PS the caps are also getting warm but not quite as much. I replaced C6 and the rail voltage came down some. Perhaps Q13 is maybe leaking some?
It seems this amp is in dire need of new CAPs, possibly at higher rated voltages. All caps in the PS which is running close to 90vDC rail are only rated for 25v & 35v. AND they're getting quite warm, especially C6 - its getting hotter than I can touch. Also in the lower PS the caps are also getting warm but not quite as much. I replaced C6 and the rail voltage came down some. Perhaps Q13 is maybe leaking some?
How much supply voltage are you driving into the amp?
The diagram I have shows ±36v. With a transformer ratio of 6:16, ±36 seems about right for about 13.5v in.
The diagram I have shows ±36v. With a transformer ratio of 6:16, ±36 seems about right for about 13.5v in.
I tried varying the supply voltage between 10-15v. The rail voltage was not changing all that much - maybe +-2vDC if that.
I've ordered all new electrolytic caps (50v) for this amp. One of the caps I removed was only testing about 30% of rated; so this amp needs that kind of love.
TIP31. I don't have any in stock and forgot to order, but I do have a LOT of MJE15030G. Compatible? Collector-Emitter Saturation Voltage is the only spec far off.
I've ordered all new electrolytic caps (50v) for this amp. One of the caps I removed was only testing about 30% of rated; so this amp needs that kind of love.
TIP31. I don't have any in stock and forgot to order, but I do have a LOT of MJE15030G. Compatible? Collector-Emitter Saturation Voltage is the only spec far off.
I think the tip31 are fine. Just replaced all caps and the amp is sitting at 70v rail both sides. This amp sounds awesome.