Schrijver
| Increase the volume of an NMS-1205?
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jpgrobler
msx lover
Berichten: 117 |  Geplaatst: 21 Februari 2004, 11:15 |
Quote:
| II've only been able to find 1 page describing this problem and also giving a solution: it suggests to replace the resistor R41 with a heavier or a variable one.
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I replaced the 10K resistor with 2x 22K resistors (44K)
The volume increased nicely on slotconnector and rca output.
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jpgrobler
msx lover
Berichten: 117 | Geplaatst: 21 Februari 2004, 11:17 |
Quote:
| II've only been able to find 1 page describing this problem and also giving a solution: it suggests to replace the resistor R41 with a heavier or a variable one.
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I replaced R41 (10K) with 2x 22K (44K) resistors
The volume increased very nicely!
JP |
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karloch
msx addict
Berichten: 417 | Geplaatst: 21 Februari 2004, 14:08 |
Did you insert two resistor in the place of the R41? I mean, two resistor in the same point.
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jpgrobler
msx lover
Berichten: 117 | Geplaatst: 21 Februari 2004, 18:47 |
Quote:
| Did you insert two resistor in the place of the R41? I mean, two resistor in the same point.
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Yes in serie so the total resistance is 44K
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dhau
msx master
Berichten: 1057 | Geplaatst: 12 Mei 2004, 23:27 |
Hi, If you connected them like this:
/---[===]---\
\---[===]---/
then you will get 22KOhm/2 = 11KOhm
If you did it like this:
---[===]---.---[===]---
Then you will get 22KOhm + 22KOhm = 44KOhm
It doesn't matter really, since you did resolved your problem 
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dhau
msx master
Berichten: 1057 | Geplaatst: 13 Mei 2004, 17:15 |
Hey JP, can you please put some photos of your hack? I mean I do have issues with volume with Philips NMS-1205 unit, and all is great with Toshiba MSX Audio...
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[D-Tail]
msx guru
Berichten: 3019 | Geplaatst: 13 Mei 2004, 17:45 |
Erm... I recall something about resistors in the Philips NMS8250 series model (so that's the 8250, 8255 and 8280). It had two resistors on the upper PCB which were incorrect, thus causing a sound malfunction. E.g. you won't hear the PSG when you've plugged a FM-PAC in. Or you just barely hear it. Maybe Repair-Bas knows more about this.
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jpgrobler
msx lover
Berichten: 117 | Geplaatst: 13 Mei 2004, 19:29 |
Like this:
---[===]---.---[===]---
I got 22KOhm + 22KOhm = 44KOhm
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dhau
msx master
Berichten: 1057 | Geplaatst: 19 Mei 2004, 03:01 |
Quote:
| Erm... I recall something about resistors in the Philips NMS8250 series model (so that's the 8250, 8255 and 8280). It had two resistors on the upper PCB which were incorrect, thus causing a sound malfunction. E.g. you won't hear the PSG when you've plugged a FM-PAC in. Or you just barely hear it. Maybe Repair-Bas knows more about this.
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Any chance you recall precise marking for those resistors on the pcboard?
I'm moving on to do some vicious upgrades on my NMS 8255 soon, first I have to expand memory in all my Sony machines from 64 to 512KB, as per maximum supported my S1985... |
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jpgrobler
msx lover
Berichten: 117 | Geplaatst: 19 Mei 2004, 05:28 |
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4fridges
msx lover
Berichten: 112 | Geplaatst: 19 Mei 2004, 10:08 |
want a mixer? got one, but i don't know it's working... Buy a little behringer mixer, for about 60 euro's you'll have a 4 channel mixer..
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