Panasonic FS-A1 black screen | MSX Resource Center (Pagina 3/3)

Champion (512)

09-04-2014, 23:42

Hello, Ralf,

You have A1, not A1F, right? If so, then, check on the slot connector +/-12V. If you will not find it - the computer will be dead on a start. It has an external PLL circuitry driving the V9938 clock. So, no +12V, no supply to the varicap, no 21MHz frequency - dead machine. Your PCB has CXA1145 encoder, so no correct clock - no video/audio (78L12 regulator is out or one of the diodes).
Didn't find schematics too, but do possess TOSHIBA FS-TM1, which is rebadged FS-A1 (had the same problem, when bought w/o power adapter). Excellent machine, BTW.

Van ralf02

Supporter (8)

10-04-2014, 07:49

@maxis: Yes, I have the Panasonic FS-A1. Do you have schematics for your FS-TM1 ? I already checked the +/- 12V directly on the two Voltage - Regulators. Today evenig I will check, if theese Voltages are on the Slot-connector-Pins, too. The 21 MHz Clock Generator next to the V9938 I tested with a clock - Counter, it is okay.

Van Daemos

Prophet (2066)

10-04-2014, 08:26

Did you allready check if the V9938 sends R, G, B and sync on a scope?

Van maxis

Champion (512)

10-04-2014, 08:44

ralf02 wrote:

Do you have schematics for your FS-TM1 ?

Nope.
I see, assuming that it boots, but you see nothing, after about 15 secs, press F8 to restart in BASIC. Then another 10 secs and you can blindly type. As suggested above, try to see whether there is any change on the RGB. Also, please, check the reset circuit (also on the slot connector). BTW, your mainboard pcb is it a single layer or two layers?

Van ralf02

Supporter (8)

10-04-2014, 19:30

Hi,

I am very happy to announce, that my Panasonic FS-A1 now is working. What happend ? I was going to check the voltages on the cartridge slot and saw, that two contact latches of the upper slot were bend to the opposite side: SoundIn was shorted with -12V and A5 with A4. When I tried, to prop the latches up, one was broken. So one cartridge probably will not work, but there is still the second slot, and thats okay.
Thank you all very much for your help.

Greetings,
Ralf

Van GUNMA747J

Expert (100)

01-04-2018, 08:57

hi guys,i have the same model,i only have rca cables.However, i am trying to do some capture of it,the screen suddenly distorts and no screen and audio at all,but the machine can still boot,i still can't figure out what causes the problem