behines
Member
This is the rest of my post on my diskless upgrade. I don't have any vital questions here, but if you see me doing anything wrong, I'd appreciate the input. I do have one question about FreHD firmware but it's not critical path.
Drive Physical + FreHD
I am installing a GoTek and a FreHD. I printed this bracket pair off of Thingaverse. After a bit of a struggle, I got the GoTek installed into the bracket. (I had to shuck the as-shipped 3.5" case, and then find a nut to mount the knob, and the display slot was oversized but I cut a backup plate from an old credit card.) I am waiting on my FreHD PCB to arrive from PCBWay.
FreHD Firmware questions:
1) I have flashed the PIC and GAL chips using Firmware 2.14. I see reference to the design itself being 2.15. Am I flashing the correct firmware?
2) I have burned a new ROM 3 into a 2716 (actually into a new-stock US-sourced CAT28C16, as I was finding it difficult to locate good 2716's). What I'm not clear on is, do you actually have to install the FreHD ROM if you have a floppy drive? Or is the ROM only needed to be able to do a floppy-less straight-to-FreHD boot? I've read that you lose the ability to do cassette ops at high speed with the FreHD ROM installed. I'm sure I won't really use the cassette much, but I plan to play with it a little as part of the vintage experience, so if the FreHD ROM isn't required, I might not swap it at first.
Drive Towers
I purchased drive towers on ebay and have installed them.
Motherboard JP1A/JP1B Cable
I was not able to locate a cable of the right length to connect JP1A and JP1B, so I had Digikey fab one to my spec (10" length). It seems perfect. I haven't "hard-folded" the bends yet in this photo. (BTW, as long as I was paying a setup fee, I asked them to make two extras. If anyone needs one, send me a message.)
Jumpers from motherboard to controller cards
The jumper cables from the motherboard to the controller cards are frayed and shot. I could not locate anything domestically or on ebay to use instead. I have read about desoldering and soldering in a header, but would like to avoid that kind of violence if necessary. I have ordered a pair of these from AliExpress in length 135mm, 20 contacts, and am hoping they work.
Power supply
For the floppy power supply, I ordered a Mean Well RPT-60B. It uses VH connectors. I ordered these parts from Jameco, they all seem to work great.
I made my own mount for the power supply out of MDF board. You can see that mechanical fabrication is not my strong suit. I made a franken-cable that plugs onto the 6-pin output of the Mean Well and provides
* Two TRS-80 controller connectors (for floppy and RS-232)
* One floppy power connector (for the GoTek)
* A 5V/GND Dupont pair for the FreHD.
* A JST connector to provide +5V/GND for an Adafruit PAM8302A sound amplifier (more in a moment)
* A grounding lug wire
Sound
For sound, I grabbed Pin 5 (the purple wire) of the DIN connector at the lower corner of the unit, and routed it to the Adafruit PCM8302A amplifier. It's a Class D and can be connected directly to a speaker. The speaker shown is an 8-ohm 0.2W item I found in my parts box. The assembly seems to make reasonable volume.
Volume control is via a 10K pot destined to be mounted to the faceplate for the FreHD. The PCM8302A includes a disable input. That is wired to a SPST switch also destined for the FreHD faceplate, which simply shorts the module's SD input to GND.
I only routed the one purple wire from the DIN connector. Since the - side of the audio is just GND, I just use system GND for that. No need to run an extra wire.
I think that covers everything I am doing. Comments, advice, "don't do that, that's stupid" all highly welcomed.
Thanks,
Brad
Drive Physical + FreHD
I am installing a GoTek and a FreHD. I printed this bracket pair off of Thingaverse. After a bit of a struggle, I got the GoTek installed into the bracket. (I had to shuck the as-shipped 3.5" case, and then find a nut to mount the knob, and the display slot was oversized but I cut a backup plate from an old credit card.) I am waiting on my FreHD PCB to arrive from PCBWay.
FreHD Firmware questions:
1) I have flashed the PIC and GAL chips using Firmware 2.14. I see reference to the design itself being 2.15. Am I flashing the correct firmware?
2) I have burned a new ROM 3 into a 2716 (actually into a new-stock US-sourced CAT28C16, as I was finding it difficult to locate good 2716's). What I'm not clear on is, do you actually have to install the FreHD ROM if you have a floppy drive? Or is the ROM only needed to be able to do a floppy-less straight-to-FreHD boot? I've read that you lose the ability to do cassette ops at high speed with the FreHD ROM installed. I'm sure I won't really use the cassette much, but I plan to play with it a little as part of the vintage experience, so if the FreHD ROM isn't required, I might not swap it at first.
Drive Towers
I purchased drive towers on ebay and have installed them.
Motherboard JP1A/JP1B Cable
I was not able to locate a cable of the right length to connect JP1A and JP1B, so I had Digikey fab one to my spec (10" length). It seems perfect. I haven't "hard-folded" the bends yet in this photo. (BTW, as long as I was paying a setup fee, I asked them to make two extras. If anyone needs one, send me a message.)
Jumpers from motherboard to controller cards
The jumper cables from the motherboard to the controller cards are frayed and shot. I could not locate anything domestically or on ebay to use instead. I have read about desoldering and soldering in a header, but would like to avoid that kind of violence if necessary. I have ordered a pair of these from AliExpress in length 135mm, 20 contacts, and am hoping they work.
Power supply
For the floppy power supply, I ordered a Mean Well RPT-60B. It uses VH connectors. I ordered these parts from Jameco, they all seem to work great.
I made my own mount for the power supply out of MDF board. You can see that mechanical fabrication is not my strong suit. I made a franken-cable that plugs onto the 6-pin output of the Mean Well and provides
* Two TRS-80 controller connectors (for floppy and RS-232)
* One floppy power connector (for the GoTek)
* A 5V/GND Dupont pair for the FreHD.
* A JST connector to provide +5V/GND for an Adafruit PAM8302A sound amplifier (more in a moment)
* A grounding lug wire
Sound
For sound, I grabbed Pin 5 (the purple wire) of the DIN connector at the lower corner of the unit, and routed it to the Adafruit PCM8302A amplifier. It's a Class D and can be connected directly to a speaker. The speaker shown is an 8-ohm 0.2W item I found in my parts box. The assembly seems to make reasonable volume.
Volume control is via a 10K pot destined to be mounted to the faceplate for the FreHD. The PCM8302A includes a disable input. That is wired to a SPST switch also destined for the FreHD faceplate, which simply shorts the module's SD input to GND.
I only routed the one purple wire from the DIN connector. Since the - side of the audio is just GND, I just use system GND for that. No need to run an extra wire.
I think that covers everything I am doing. Comments, advice, "don't do that, that's stupid" all highly welcomed.
Thanks,
Brad
