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Casio PV-16 Troubleshooting Guide

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Casio PV-16 CPU board
PV-16 CPU board: CPU, BASIC ROM and the two RAM chips

No fault-finding guide or circuit diagram for the Casio PV-16 has been published. The checks below use the MSX Resource Center wiki, photographs of the boards, and a PV-16 repair discussed on the MSX Resource Center forum, together with faults found on the closely related Casio PV-7, which uses the same MB64H131 gate array and TMS9118NL video chip.[1]

Start with the supply

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  1. Check the adaptor: the AD-4110 needs 100 V AC and gives unregulated 10 V DC, centre negative.[1]
  2. Measure +5 V at the cartridge slot, between pin 45 or 47 and pin 41.[2] Pins 48 and 50 carry nothing on the PV-16.[1]
  3. If +5 V is missing with 10 V at the power jack, check the µPC7805H regulator beside the jack and the capacitors round it.[3]

Symptoms

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Symptom Check first Notes
Black screen and no sound after a freeze; power lamp on RAM, ROM, CPU and video chip, after the supply On one PV-16 the adaptor was good and the regulator gave 5.2 V, and no capacitor was leaking. The machine would not start with a RAM cartridge either. Advice was that a video RAM fault alone would still let the machine beep at start-up, so a silent black screen points first at the RAM, ROM, CPU or video chip; the RAM is the two µPD4168C-20 on the CPU board and the ROM the HN613256P D19 beside them. The outcome was not reported.[4]
Black screen The MB64H131 and the TMS9118NL On a damaged PV-7 both of these had failed, and each gave a black screen; the PV-16 uses the same two chips.[4][1]
Black screen with no clock at the CPU The TMS9118NL On a PV-7 the dead video chip stopped the clock to the CPU as well. A replacement must be a TMS9118, because a TMS9918A expects a different type of video RAM.[5]
Odd faults on an old board Wire links and solder joints Check that no ceramic capacitor touches a wire link, and reflow any dull or cracked joints.[4]
FM-PAC or other ±12 V cartridge does not work The slot has no ±12 V Casio left these pins unconnected.[1]
Only 16 KB free after a RAM upgrade in slot 0 The MB64H131's slot 0 decoding A 32 KB chip in place of the two 8 KB chips still gave 16 KB on one PV-16; working upgrades put the extra RAM in slot 2.[6]
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References

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  1. ↑ 1.0 1.1 1.2 1.3 1.4 Casio PV-16, 24 July 2026—link(accessed 2026-10-21) Improved version of the PV-7; 16 KB RAM in slot 0; video TMS9118NL; audio AY-3-8910A; gate array Fujitsu MB64H131; Z80A from NEC (D780C-1); AC adaptor AD-4110, unregulated DC 10 V up to 800 mA, centre negative, from AC 100 V; cartridge pins SW1, SW2, −12 V and +12 V not connected.
  2. ↑ MSX Cartridge slot, 6 July 2026—link(accessed 2026-10-21) Pin table: 41 and 43 GND; 45 and 47 +5 V; 48 +12 V; 50 −12 V.
  3. ↑ Photograph of the PV-16 main board (File:Casio PV-16 main board.jpg), uploaded to the MSX Resource Center wiki by Gdx on 15 February 2016: power jack and power switch at the top edge, µPC7805H regulator beside them, with electrolytics marked on the board 100 µF 25 WV and 100 µF 6.3 WV.
  4. ↑ 4.0 4.1 4.2 Black Screen, March 2018—link(accessed 2026-10-21) cobracon2: a PV-16 froze during a game and then showed a black screen, with no sound, the power light on, and no change with a 1 MB memory cartridge; the power supply checked good, the regulator gave 5.2 V, no capacitors leaked or bulged; the CPU board appears soldered. Grauw: the RAM is 2 × µPD4168C-20 on the CPU board and the ROM the HN613256PD19; if there is no sound it is probably not a VRAM problem, because the machine should still boot without it; check for chips that run hot. gdx: check that the ceramic capacitors do not touch the straps and check all the solder joints. jltursan: the MB64H131 failed in a PV-7 he repaired, which also needed a new VDP; both faults gave a black screen, and the PV-16 uses the same chip.
  5. ↑ Repairing a Casio PV-7, February 2024—link(accessed 2026-10-21) lmanes, 10 and 11 February 2024: on a PV-7 there was no clock signal on the CPU or on the VDP and the VDP was the fault; a TMS9918A fitted in its place gave only border and background colour, because it uses 16K × 1 video RAM where the PV-7's TMS9118NL uses TMS4416 chips; a TMS9118NL taken from a PV-16 made the PV-7 work.
  6. ↑ Casio PV-16 upgrade to 32kb on slot 0 won't work, November and December 2023—link(accessed 2026-10-21) lmanes: a single 32 KB chip in slot 0 with A13 and A14 wired still showed the same free memory in BASIC. gdx: the MB64H131 seems to filter /SLTSL0 for the page 3 RAM only; the known 64 KB upgrades wire the RAM to /SLTSL2, after which the KB-7 can no longer be used.


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