Try a service manual. A quick Google have me this:
https://www.manualslib.com/manual/895227/Harman-Kardon-Avr7300.html
Must say I did not read it, but hope it helps!
Edit: Ok, now I read parts of it. It does not state exact specs, but the schematics should be helpful for both of you 🙂
https://www.manualslib.com/manual/895227/Harman-Kardon-Avr7300.html
Must say I did not read it, but hope it helps!
Edit: Ok, now I read parts of it. It does not state exact specs, but the schematics should be helpful for both of you 🙂
Last edited:
Hi,
I am in a similar situation. Got it from a work colleague. All beautiful displays come to life but no sound. In fact after taking it apart and putting back I get sound from 2 channels but if I change the source it doesn't produce any sound. Coming back to teh previous position doesn't change anything. Such a shame.
But it has nice heat sinks inside.
Anyway, coming back to your question the amp boards use +-55V. That is after regulation obviously. So my guess would be 2x55VAC give or take.
I am in a similar situation. Got it from a work colleague. All beautiful displays come to life but no sound. In fact after taking it apart and putting back I get sound from 2 channels but if I change the source it doesn't produce any sound. Coming back to teh previous position doesn't change anything. Such a shame.
But it has nice heat sinks inside.
Anyway, coming back to your question the amp boards use +-55V. That is after regulation obviously. So my guess would be 2x55VAC give or take.
> the amp boards use +-55V. That is after regulation obviously.
Power amps rarely fed regulated power. My bet would be 40V-0V-40V.
This can readily be checked if you can identify the wall-cord winding and use a dim-bulb limiter.
It can power essentially what the original was rated. Two channels at >125W 8r each steady-state. It can power seven channels at >100W (or probably two at 4r at >200W) as long as it is speech/music/movies and not steady test-tone.
Power amps rarely fed regulated power. My bet would be 40V-0V-40V.
This can readily be checked if you can identify the wall-cord winding and use a dim-bulb limiter.
It can power essentially what the original was rated. Two channels at >125W 8r each steady-state. It can power seven channels at >100W (or probably two at 4r at >200W) as long as it is speech/music/movies and not steady test-tone.
The transformer seems to have a large number of secondaries.
If you look at the manual page 154 and 157 most of the voltages are shown.
So there seems to be:
10V-0-10V
17V-0-17V
20V-0-20V
45V-0-45V (main power for output stage)
48V-0-48V
There are also secondaries S6 and S7. Voltages are not shown on page 157.
On page 150:
The (AC)-0-(AC) seems to be used for a +10V unregulated supply, which is used for the fan and the 5V and 3.3V regulators.
The other secondary is just called AC. It is used for a +44V supply for the display board, probably at a low current level.
The currents needed are not shown, so it will take some further study to calculate/estimate them.
By the way, is the transformer faulty and you want to replace it, or do you want to reuse the transformer for something else?
If you look at the manual page 154 and 157 most of the voltages are shown.
So there seems to be:
10V-0-10V
17V-0-17V
20V-0-20V
45V-0-45V (main power for output stage)
48V-0-48V
There are also secondaries S6 and S7. Voltages are not shown on page 157.
On page 150:
The (AC)-0-(AC) seems to be used for a +10V unregulated supply, which is used for the fan and the 5V and 3.3V regulators.
The other secondary is just called AC. It is used for a +44V supply for the display board, probably at a low current level.
The currents needed are not shown, so it will take some further study to calculate/estimate them.
By the way, is the transformer faulty and you want to replace it, or do you want to reuse the transformer for something else?
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