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Re: A full Spectrum of emotions
Posted: 19 Sep 2023 21:52
by HigashiJun
rubber_jonnie wrote: 19 Sep 2023 15:10
I 'might' come over to Japan in 2025, not 100% sure as yet, but my Karate club do a trip to Okinawa annually and I might go.
You definitely should !
Re: A full Spectrum of emotions
Posted: 19 Sep 2023 22:39
by rubber_jonnie
HigashiJun wrote: 19 Sep 2023 21:52
rubber_jonnie wrote: 19 Sep 2023 15:10
I 'might' come over to Japan in 2025, not 100% sure as yet, but my Karate club do a trip to Okinawa annually and I might go.
You definitely should !
Bit of planning to do first :)
Re: A full Spectrum of emotions
Posted: 19 Sep 2023 23:41
by rubber_jonnie
Well, that was a narrow squeak!!
I stole the missing transistor for the + from the spares board, figured out the pinout using my component tester and installed in the board.
Since the 12v side of the power is all I need now the RAM has been replaced, I had the multimeter ready to check the voltage as soon as I plugged the power in.
Well I got a shock, suddenly the circuit is delivering 29v!!!
Luckily I was on the ball and unplugged immediately, so no harm done, but more than a little confused that the 12v circuit was suddenly delivering more than twice the voltage it's supposed to be. Ho hum.
I bloody hate power supply circuits at times :(
At least no harm done because I was quick off the mark pulling the power.
Re: A full Spectrum of emotions
Posted: 20 Sep 2023 00:04
by exxos
Is there a circuit for it ?
Re: A full Spectrum of emotions
Posted: 20 Sep 2023 10:22
by HigashiJun
@rubber_jonnie
29 volts !!! You were really lucky not to fry your machine...
Re: A full Spectrum of emotions
Posted: 20 Sep 2023 12:01
by stephen_usher
HigashiJun wrote: 20 Sep 2023 10:22
@rubber_jonnie
29 volts !!! You were really lucky not to fry your machine...
Only one chip would be on the +12V rail with all the RAM replaced with hacked 4164 chips, the LMxxxx video encoder.
Re: A full Spectrum of emotions
Posted: 20 Sep 2023 13:29
by rubber_jonnie
stephen_usher wrote: 20 Sep 2023 12:01
HigashiJun wrote: 20 Sep 2023 10:22
@rubber_jonnie
29 volts !!! You were really lucky not to fry your machine...
Only one chip would be on the +12V rail with all the RAM replaced with hacked 4164 chips, the LMxxxx video encoder.
Luckily the LM1889 survived, and I have spares at least.
Re: A full Spectrum of emotions
Posted: 20 Sep 2023 15:06
by stephen_usher
exxos wrote: 20 Sep 2023 00:04
Is there a circuit for it ?
Here you go...
Spectrum-Power-Circuit.jpeg
TR4 isn't marked, but it's the lower of the two transistors.
Re: A full Spectrum of emotions
Posted: 20 Sep 2023 15:12
by stephen_usher
If the coil is faulty and the output side is partly shorted then I guess the ratio between the two coils would be different causing the voltage to change.
Those coils are well known to fail.
Re: A full Spectrum of emotions
Posted: 20 Sep 2023 15:42
by rubber_jonnie
stephen_usher wrote: 20 Sep 2023 15:06
exxos wrote: 20 Sep 2023 00:04
Is there a circuit for it ?
Here you go...
Spectrum-Power-Circuit.jpeg
TR4 isn't marked, but it's the lower of the two transistors.
What issue is that Stephen? Mine is closer to the issue 5 (I can't find a 4s specific schematic) IIRC I did check for shorts in the coil but I can do so again. It's a fairly rudimentary device that's for sure.