8" drive on AMPRO LittleBoard Z80?

[Ragnarock]

Has anyone seen any documentation for putting a standard SSSD 8" drive on an AMPRO Z80 Littleboard?

 

[Chuck(G)]

Even if you install U6 to provide a doubled-clock, your problem is the WD1770, which isn't rated for the doubled data rate of 8" drives. Your best bet is the WD1770PH02 02; otherwise it's hit-or-miss.

The rest is just cabling and software.

 

[Ragnarock]

It has a 1772-PH in it, along with U6.

The dual drives in this thing are single-sided.
I've been able to boot with a double-sided 5.25 drive and the diskimage from Dunfield, so making progress.

While trying to figure out how to build a single-sided diskette with the utilities, I lost a RIFA cap in the power supply.
PSA523B by MJC. No docs found online. I'm getting cornered.
It blew the top off and I can see the value

 

[ldkraemer]

Is it one of these values?
http://www.akhara.com/trs-80/psrepair/index.html


Larry

 

[Chuck(G)]

It has a 1772-PH in it, along with U6.

Read the line below the "WD1772PH". If it reads "02 02", you stand a good chance of getting the chip to work at 16MHz, though it will probably run hot. (early 80s CMOS wasn't that fast). Not all WD1772PH02 02s can--it's a "try it and see" affair. I don't know if Best still sells the custom AJAX chip, which can do the job, but I don't know if Best is still in business.

FWIW, the WD1770, 1772 and 1773 are all basically the same chip with different signals brought out. The 28 pin package was somewhat limiting.

 

[Ragnarock]

It has "00-02" on it.

This SCSI port makes me wonder about using a SCSI-to-SD card system.
Have you ever seen that done on a little board?

I think the cap is .1uf. Have ordered a replacement.

Trying to find a pair of half-height 40 track double-sided drives to replace the single-sided ones.
Most of the half-height drives on ebay are 80 track, and most of the 40 track are full height.

 

[Chuck(G)]

There are a few Teac FD-55Bxxx drives on eBay. It depends on how much you'd like to pay.

The really insane $$$ prices for the FD-505 combo drives has my head spinning. I still have most of a carton of the things NOS. Maybe I should cash in...

The WD1772PH 00 02 chip will likely not support the 16MHz clock. Some of the 02 02 chips will.

 

[exidyboy]

Trying to find a pair of half-height 40 track double-sided drives to replace the single-sided ones.
Most of the half-height drives on ebay are 80 track, and most of the 40 track are full height.

Mitsubishi M-4851s show up from time-to-time on ebay US at reasonable prices.