FAULTY VFD SCREEN - ROMTEC FROG PRINCE

BAH

Hi, the VFD screen on my Romtec Frog Prince is showing the red vertical filaments lighting up, but not the graphics themselves. The sound and controls seem to be working ok (I can hear the frog moving when I use the joystick). Can someone please offer advice on what the problem is and how the graphics can be fixed. Thank you - BAH

blanka · Posted: Tue Jun 19, 2012 12:53 am Post subject:

If the filaments glow, the filament voltage seems OK. Can you give me the number of the Microcontroller. Then I can give you the pins to measure to check if the Vdisplay from the power supply is OK. Seems that that part is wrong.

BAH · Posted: Tue Jun 19, 2012 1:50 am Post subject:

Thank you, Blanka. There is a masking tape like strip fixed fast on the microcontroller chip, which I gather works as insulation between it and the VFD screen in which it is directly behind. I can't make out any identifying markings. The chip has 21 pins and the screen has 33 pins if that helps.

blanka · Posted: Tue Jun 19, 2012 2:41 am Post subject:

21 pins on both sides I may hope? 42 in total. Does it have 2.5mm pin spacing or 2mm? Are pin 15,16 and 17 connected together? If you look to the chip from above, and you align the small gap on one side upward, pin 1 is the pin to the right of that gap.
Does the print have resitorbanks between the chip and the vfd (long black or blue 8-12 pin items).
Usually I roll off the tape and glue with my finger. It comes off easily.
Or post both side pcb pictures, so I can anwer all these questions myself Smile

BAH · Posted: Tue Jun 19, 2012 4:40 am Post subject:

42 pins with 2.5mm between pin points. Points 15, 16 and 17 are soldered together on the board. There are other resistors, but nothing 8-12 pins. I took the tape off and it reads '3DI HD38800831 JAPAN'.
I can't post a pic here. Can you give me an email address I can send it?