quadram power supply question

[Jjona5]

I just bought a PCJR from a computer store and it has a quadram installed on it. Does that mean it needs a power supply and the actual pcjr needs one as well? Has anyone made an all in one solution? My first computer was a pcjr and I've been quietly searching for another and stumbled upon this one. Also do I need to do anything to get the computer to recognize the expansion?

Thanks in advance,
Jonathan

[Jjona5]

Well I found this https://www.brutman.com/PCjr/docs/Rappo ... lation.pdf

Helps out a bit but I guess I'll need to get a copy of the disks from somewhere. Can an IDE mod be done while keeping this ram expansion?

[Jjona5]

If I use one of the pico power supplies, since the original used 35w, if I bought an 80w pico, do you guys think I could build a jumper cable and get rid of the quad ram power supply as well? OH also the other PCJR I picked up has a tecmar jrcaptain.

[alanh]

You could probably get by jumpering up the power supply cables from one if you didn't have any extra side cars.

RAM expansions can overlap without much issue. Both RAM parts mapped to the same addresses will latch and drive the same data. But since they have different response timings, there may be points where opposing drivers are active causing higher power consumption and quicker part life degradation. Avoid it if possible. But the with the duty cycle most vintage machines get on shelves and the occasional work-bench - it doesn't matter much.

[bagelswitch]

If I use one of the pico power supplies, since the original used 35w, if I bought an 80w pico, do you guys think I could build a jumper cable and get rid of the quad ram power supply as well? OH also the other PCJR I picked up has a tecmar jrcaptain.

I'm using a pico PSU, and I power my Racore drive expansion board just via it's floppy molex connector - ie. I just have effectively an "X" cable that connects the molex connectors on the Jr's power supply, the Racore expansion supply, and the two drives (original IBM 360k drive in the expansion chassis, GoTek emulator in the Jr. base) - there is nothing connected to the "outside" power input of the Racore expansion at all.

[Jjona5]

Thanks for the help. I hate to buy a power supply only to test but I'm not sure what I need to power in the expansion. If I had an extra power supply I could get the meter out and just make some jumpers. Also do you guys happen to know what size the connector for a Tecmar Jr. Captain is? I found one that puts out the 8.5vac but I was hoping to order the connector also.

[Gremlin5]

If your other PCJr is going to use a pico power supply you can just run a 5 volt line and power your Tecmar Jr Captain off that. I have 2 Tecmar JR Captains and one of them I just ran a 5 volt line off the Jr and power it that way, the other Tecmar JR Captain came with an original Tecmar power supply but the previous owner must have had some problem with the barrel connector as he cut it off and hard wired its leads right to the JR Captain.