I recenty acquired a partially working X68000 (OG model, CZ-600C). I decided to rebuild the PSU using a Mean Well RPTG-160B instead of using a Pico PSU and wanted to share my findings.
I originally had this Mean Well PSU planned for another project (Macintosh IIci PSU) but decided to use it for the X68000 instead.
The RPTG-160B provides 5V (14A), 12V (5.5A) and -12V (1A) as well as 5V standby power.
I designed a PCB with mounting holes that fit the standoffs of the original PSU enclosure. The Mean Well PSU is mounted on top of that PCB, on another set of standoffs. I added JST connectors to the original wire harness and those connect to the PCB.
After reading the datasheet of the RPTG-160 my understanding was that its soft power works like an ATX PSU, so I added a power-on circuit to the PCB that is similar to what is used in most ATX PSU conversions. However it turns out that this is not the case and the Mean Well soft power is compatible with the CZ-600C without any additional components. So far I am happy with the results.
Now I saw that newark.com is selling the RPTG-160A (provides -5V but no -12V) for only $25.80, which I think is a great price. So I went ahead and ordered 3 of those.
My new plan is to get rid of the unused power-on circuit on my PCB and use the space to generate -12V intead.
CZ-600C-RPTG-160B.jpg
Nice work.
With 14A on the 5V line I don't think your ever going to hit capacity 😂
Interesting, but how do you think to get the -12v? It would be easy to convert the -12v to -5v, but not viceversa
Quote from: aotta on January 07, 2024, 06:57:43 AMInteresting, but how do you think to get the -12v? It would be easy to convert the -12v to -5v, but not viceversa
My plan is to try CUI VXO78012-500 and/or Mean Well DPBW06F-12.
I ordered new PCBs that are compatible with RPTG-160A, B and in theory D (untested).
A and D models need CUI VXO78012-500 and/or Mean Well DPBW06F-12 + a couple passives according to the data sheets of those parts. Since I have 5 PCBs from JLCPCB I built both variants for RPTG-160A and the variant for the RPTG-160B.
If the remaining two PCBs are useful for anyone, please let me know.
I am now using the one with the RPTG-160A and DPBW06F-12 in my X68000.
I had never ordered from newark.com before, they shipped the 3 PSUs without any kind of packaging or padding between the units, so they now have scratches on the PCBs and heat sinks.
They now also raised the price for the RPTG-160A again.
However their customer service gave me a refund, so that worked out well for me.