PC-FX PSU resistor indexing

[Ptolomey I]

Hi,

I've recently acquired a non-functional NEC PC-FX console and I'm trying to fix it
First actions are cleaning the components and replacing all the caps in the console (cap maps found online)
None of the caps on the PWA & PWH boards were leaky, and that gives me hope to continue with the project!

My blocking point is the PSU: the Tamura TK-MF5, 2P-P1-2316
All the caps on the board were leaky and corrosion spreaded all over the board (especially on the right area):


 Since I couldn't find any PSU replacements available at the moment, I've decided to try to fix it I've removed caps, transformer, transistors and heat sinks to give the board and these elements a thorough clean After removing A LOT of corrosion, the board is now looking as this:


The problem is that the corrosion attacked a number of resistors so heavily that the color coding was unreadable, and some of them were completely gone even Now I need to find replacements for items whose resistance I don't know I have tried to find any schematics or info online, but I couldn't find anything

So, I am asking if anyone that has a PC-FX console could check if they have a similar PSU, and could let me know the color codes or the ohm values of the following thirteen resistors (circled on this pic):


    R10
    R12
    R13
    R15
    R16
    R17
    R19
    R20
    R22
    R23
    R24
    R25
    R26

I understand that this is a very specific request, so if you can redirect me to some sources or any other help would also be greatly appreciated!
Thanks!

PC-FX PSU

[NightWolve]

Hi @Ptolomey I, welcome to the forum!

Darn, so you missed @Keith Courage by 2+ weeks ago, and @thesteve was here a month ago. They are our EE/repair experts for PCEFX hardware. I'll have to ping them to take a look at your problem since this forum is very slow. I'll also ask at the PCFX Club.

(Your image links were broken but I patched them to work, FYI)

EDIT: @dshadoff thinks https://x.com/zaxour on Twitter/X has reverse-engineered the PSU in order to make a new one and maybe he's got the values and/or a schematic. So I'll ask!

UPDATE: After some reverse Google image searches, I found you your model (2P-P1-2316):


UPDATE: I got a HiDef photo of the PSU from Dave, so if you just wanna try resistor replacement here you go. But upon comparison, I notice it's slightly different than yours. So you got the other model, there are 2 with slight differences.



Plan B: You're in luck! How about a new/modern, efficient model designed by a fan ??

willsconsolemodifications.co.uk/index.php?route=product/product&language=en-gb&product_id=92



There's also this if you wanted to build it yourself, another universal PSU design:
https://github.com/Unstablewarpfield/PC-FX-Uni-PSU


Lastly, someone found a YouTube video for you where lucky enough YOUR PSU model is liberated from the system for some repairs. Several times it's being moved back and forth, giving you a better chance to see the resistor color-codings. Good luck!

[Ptolomey I]

Hi @NightWolve,

Thank you very much for your quick, comprehensive, and useful reply!!
Thanks as well fpr fixing my image links

I want to comment on a couple of the points you raised:
The Plan Bs:

• Unfortunately it seems that Will is going through a rough patch and the products as his store are unavailable. I hope he can overcome these hard times soon!
• Thanks for the PC-FX universal PSU! if this resistor indexing doesn't work I may follow that route

High-res images & video
These resources have been super useful! By combining them I ting I've been able to map out all the resistors in my PSU correctly (not only the disintegrated ones)

In case anyone in the future is found in a similar situation as I, here's a table I hope would be useful:

Item	Nominal value (Ohm)	Tolerance	Same among 2 PSUs?	Number of rings	1st	2nd	3rd	4th	Tolerance
R1	470	+/-5	O	4	Yellow	Violet	Yellow	--	Gold
R2	150	+/-5	?	4	Brown	Green	Yellow	--	Gold
R3	150	+/-5	?	4	Brown	Green	Yellow	--	Gold
R4	47	2W	?	--
R5	33	330J/1W	?	--
R6	33	330J/1W	?	--
R7	1500	+/-5	?	4	Brown	Green	Red	--	Gold
R8	EMPTY
R9	EMPTY
R10	330	+/-5	O	4	Orange	Orange	Brown	--	Gold
R11	12	+/-5	O	4	Brown	Black	Red	--	Gold
R12	2200	+/-5	O	4	Red	Red	Red	--	Gold
R13	110	+/-1	?	5	Brown	Brown	Black	Brown	Gold
R14	--		?
R15	820	+/-5	O	4	Grey	Red	Brown	--	Gold
R16	560	+/-5	O	4	Green	Blue	Brown	--	Gold
R17	220	+/-5	O	4	Red	Red	Brown	--	Gold
R18	--		?
R19	680	+/-5	?	4	Blue	Grey	Brown	--	Gold
R20	82	+/-5	O	4	Grey	Red	Black	--	Gold
R21	15	+/-5	O	4	Brown	Green	Black	--	Gold
R22	2700	+/-5	O	4	Red	Violet	Red	--	Gold
R23	4700	+/-5	O	4	Yellow	Violet	Red	--	Gold
R24	26800	+/-1	O	5	Red	Blue	Grey	Red	Brown
R25	4300	+/-1	O	5	Yellow	Orange	Black	Brown	Brown
R26	10000	+/-5	O	4	Brown	Black	Orange	--	Gold

I misI will order the resistors I need + 1 0.47uF capacitor I missed on the PWA board.
Other than that, the rest of the console is already recaped:



I believe someone online was asking for a cap map on the PC-FX, I will do it as well.

I will keep you updated on the progress on the console, thanks again!

[NightWolve]

Glad we could help!

For capacitor info, check console5 too since they sell capacitor kits.

console5.com/store/nec-pc-fx-tamura-power-supply-psu-cap-kit.html
wiki.console5.com/wiki/PC-FX