WD1772-0202 - overheats at 16MHz

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troed
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WD1772-0202 - overheats at 16MHz

Post by troed » Sun Feb 04, 2018 5:02 pm

"Back then everyone knew that the WD1772-0202 could do 16MHz, thus 1.44MB"

Yeah I've said that myself many times. So when I bought my Mega STE (TOS 2.05, 720KB drive, -001 PAL) and saw it had the -0202 I immediately set out to upgrade it with a proper GAL and Epson 340 drive. And verified it indeed worked fine in both 720KB and 1.44MB modes.

Well, except for now when I really want to use it. My Falcon hasn't got any storage medium equipped (besides internal IDE-CF) so I'm using floppy to transfer sw at the moment. And after several days of testing I can now conclude that my Mega STE, after having been turned off for a while, is able to write a bit more than a full 1.44MB disk until it starts giving up errors, and finally stop understanding HD disks at all. However, 720KB disks work perfectly all the time.

Turn it off, let it cool down, and I can write another disk ...

I guess I simply have a -0202 that's unable to run in 16MHz for any extended amounts of time :/ Pondering to put some cooling paste and a sink on top of it to see if it helps. It's underneath the SCSI controller so I haven't felt to see how hot it gets yet. But disconnecting the (noise and heat generating) SCSI drive and opening up the drive bay hasn't made a difference.

The only spare 1772 I have is a VL ... but it can't become much worse.

Meh.

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Re: WD1772-0202 - overheats at 16MHz

Post by exxos » Sun Feb 04, 2018 5:24 pm

The vl1772 do get hotter than the wd1772s. Its pot luck if they work at 16mhz or not. Though most which do run at 16mhz can still overheat after serious usage. But, this is why my HD designs switch back to 8mhz when the 1772 is not in use. So I class the 1772s I sell as 16mhz capable if they can format/copy extended format floppies several times. I never saw any failure even after a lot of formats spanning a hour or so,but the chips run mostly 16mhz all the time anyway.

Though some kits may run at 16mhz constantly which would likely overheat and start causing failures. Though I never tested such things personally. It could be anywhere from a hour to several hours.

Normally if a 1772 isn't 16mhz capable it shows up on the very first format. Though jury is out how long it would function running all day at 16mhz. I can only speak of my kits, I don't know how the mste works with speed switching. Might be worth scoping it out ?
4MB STFM 1.44 FD- VELOCE+ 020 STE - 4MB STE 32MHz - STFM 16MHz - STM - MEGA ST - Falcon 030 CT60 - Atari 2600 - Atari 7800 - Gigafile - SD Floppy Emulator - PeST - HxC - CosmosEx - Ultrasatan - various clutter

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Re: WD1772-0202 - overheats at 16MHz

Post by troed » Sun Feb 04, 2018 5:30 pm

exxos wrote:
Sun Feb 04, 2018 5:24 pm
I don't know how the mste works with speed switching. Might be worth scoping it out ?
AFAIK TOS sets (that's what the GAL does) the speed of the 1772 depending on whether it's able to access valid sector contents or not. Whether it leaves the chip in 16MHz until next (failed) sector read I don't know, but it's reasonable. Good idea to scope - will do :)

It was already socketed so put the VL chip in now. Formatted (with a few retries) and now writing files ...

Oh well, busting myths ("all -0202 work!") is also creating new knowledge .. ;)

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Re: WD1772-0202 - overheats at 16MHz

Post by exxos » Sun Feb 04, 2018 5:40 pm

troed wrote:
Sun Feb 04, 2018 5:30 pm

Oh well, busting myths ("all -0202 work!") is also creating new knowledge .. ;)
Indeed. 0202 was later and more likely to work, in theory. But I've tested 100s over the years and its just pot luck. I class the vl as old tech, seen them in old BBC machines. Some of those work, and some 0202 don't.
4MB STFM 1.44 FD- VELOCE+ 020 STE - 4MB STE 32MHz - STFM 16MHz - STM - MEGA ST - Falcon 030 CT60 - Atari 2600 - Atari 7800 - Gigafile - SD Floppy Emulator - PeST - HxC - CosmosEx - Ultrasatan - various clutter

https://www.exxoshost.co.uk/atari/ All my hardware guides - mods - games - STOS
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Re: WD1772-0202 - overheats at 16MHz

Post by troed » Sun Feb 04, 2018 5:55 pm

exxos wrote:
Sun Feb 04, 2018 5:40 pm
troed wrote:
Sun Feb 04, 2018 5:30 pm

Oh well, busting myths ("all -0202 work!") is also creating new knowledge .. ;)
Indeed. 0202 was later and more likely to work, in theory. But I've tested 100s over the years and its just pot luck. I class the vl as old tech, seen them in old BBC machines. Some of those work, and some 0202 don't.
Yeah I'm getting exactly the same symptoms with the VL .. was able to format and write to one disk, after a while having done other things it was a no-go. Formatting DD works fine.

I'm still suspecting the 1772 because I can't really see anything else that would produce the same symptoms :) I guess I have to pull a known working 16MHz chip from one of my other machines and make sure.

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Re: WD1772-0202 - overheats at 16MHz

Post by exxos » Sun Feb 04, 2018 11:29 pm

I would assume the MSTE stays in 1.44 mode (16mhz) until you access a 720K floppy again.. I guess you could format a 1.44, swap to a 720k read the disk.. leave it for a hour.. then try a 1.44 again.. would assume it would work ok in that test.
4MB STFM 1.44 FD- VELOCE+ 020 STE - 4MB STE 32MHz - STFM 16MHz - STM - MEGA ST - Falcon 030 CT60 - Atari 2600 - Atari 7800 - Gigafile - SD Floppy Emulator - PeST - HxC - CosmosEx - Ultrasatan - various clutter

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Re: WD1772-0202 - overheats at 16MHz

Post by arf » Mon Feb 05, 2018 6:33 pm

troed wrote:
Sun Feb 04, 2018 5:02 pm
[…]
I guess I simply have a -0202 that's unable to run in 16MHz for any extended amounts of time :/ Pondering to put some cooling paste and a sink on top of it to see if it helps. It's underneath the SCSI controller so I haven't felt to see how hot it gets yet. But disconnecting the (noise and heat generating) SCSI drive and opening up the drive bay hasn't made a difference.
Is there any chance that a source of AJAX chips pops up again itf? Is there a chance for clones? Anybody ever heard of sth like that?
--
Against signature spam!

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Re: WD1772-0202 - overheats at 16MHz

Post by stephen_usher » Mon Feb 05, 2018 7:15 pm

Doesn't Best Electronics still sell them (If you can get them to actually sell you anything)?
Intro retro computers since before they were retro...
ZX81->Spectrum->Memotech MTX->Sinclair QL->520STM->BBC Micro->TT030->PCs & Sun Workstations.
Added code to the MiNT kernel (still there the last time I checked) + put together MiNTOS.
Collection now with added Macs, Amigas, Suns and Acorns.

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Re: WD1772-0202 - overheats at 16MHz

Post by exxos » Mon Feb 05, 2018 7:21 pm

stephen_usher wrote:
Mon Feb 05, 2018 7:15 pm
Doesn't Best Electronics still sell them
They still have them listed, half price when I looked the other day IIRC.
stephen_usher wrote:
Mon Feb 05, 2018 7:15 pm
(If you can get them to actually sell you anything)?
Not just me who has that trouble then! :roll:
4MB STFM 1.44 FD- VELOCE+ 020 STE - 4MB STE 32MHz - STFM 16MHz - STM - MEGA ST - Falcon 030 CT60 - Atari 2600 - Atari 7800 - Gigafile - SD Floppy Emulator - PeST - HxC - CosmosEx - Ultrasatan - various clutter

https://www.exxoshost.co.uk/atari/ All my hardware guides - mods - games - STOS
https://www.exxoshost.co.uk/atari/last/storenew/ - All my hardware mods for sale - Please help support by making a purchase.

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Re: WD1772-0202 - overheats at 16MHz

Post by stephen_usher » Mon Feb 05, 2018 8:06 pm

exxos wrote:
Mon Feb 05, 2018 7:21 pm
stephen_usher wrote:
Mon Feb 05, 2018 7:15 pm
Doesn't Best Electronics still sell them
They still have them listed, half price when I looked the other day IIRC.
stephen_usher wrote:
Mon Feb 05, 2018 7:15 pm
(If you can get them to actually sell you anything)?
Not just me who has that trouble then! :roll:
Hehe. Brad tried to dissuade me from buying most of what I wanted and refused to sell me a mylar TT keyboard map. I did get the TOS 3.06, TT power supply and, in the end, the Ajax chip and 1.44MB drive. I had to persuade him that I knew that it was not guaranteed to work and I wouldn't blame him or ask for the money back.

He's also stuck in the mid-90s, both his HTML 1.0 web site and the publicity material he sends in with the purchases.
Intro retro computers since before they were retro...
ZX81->Spectrum->Memotech MTX->Sinclair QL->520STM->BBC Micro->TT030->PCs & Sun Workstations.
Added code to the MiNT kernel (still there the last time I checked) + put together MiNTOS.
Collection now with added Macs, Amigas, Suns and Acorns.

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