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Paul Westphal

1050 US Doubler Speed

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You could try putting the original 6810 and ROM back in. Have you tried both single and double density writes with the USD in place?

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yep to writes.

 

the format thing is odd. it spins up to format and the head remains in same place - as if it were formatting, but doesn't move from the same spot.

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the format thing is odd. it spins up to format and the head remains in same place - as if it were formatting, but doesn't move from the same spot.

 

Sounds like the FDC is not getting the index pulse, which in the case of the 1050 is "faked" from the PIA.

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ok, update:

 

having swapped out all ICs - for working ones and good (mech/stepper) still get exactly the same results using this board

 

latest video:

 

 

 

 

one other thing, the rear metal (aluminium) colour shielding is getting hot

 

 

 

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check the rpm's of the drive and the alignment.... when is the last time the head was cleaned?

since it boots and steps...it's not all that bad... the heat sink will get pretty darn warm in fact that's normal.... if it truly is getting too hot (Thermal runaway) then you should check the voltages off the regulators attached to the heat sink... get readings while cold and then get readings while hot.... if the voltages vary too greatly or are out of spec... look towards replacing them and other parts of the power supply... capacitors have been known to go bad on the 1050.... in any event.... clean and check rpm are at 288... then move to the other preliminary check as mentioned

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RPM - not a problem. i've swapped in a known good mech and stepper - same result

 

am convinced this is a board issue. but stumped by it

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having swapped out all ICs - for working ones and good (mech/stepper) still get exactly the same results using this board

 

You replaced all the ICs? That means you removed the US Doubler altogether and installed back a stock 1050 ROM as well?

 

It could be the board, or a socket, of course. Not the most common failure but certainly not impossible. Would be difficult to diagnose without a scope or a LA at least.

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Yep and the index pulse circuit, the 1050 of course had no emitter or detector.. It is faked....laying down the first sector and timing off that thereafter....

so u21 and cr10 and the connectors attached correctly seems to be a theme...

Edited by _The Doctor__
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Well, I've made my 1st US Doubler RAM pack all by myself after sourcing parts from odd places around the world for a good price on eBay. I had 1 working RAM pack that my dad put together in the early 90's that I've been using recently in my endeavours learning how to burn my own EPROMS (including US Doubler), trying different USD / Stock 1050 code, so this was the next step.

 

Thank you for this very informative thread, Kyle22, MEtalGuy66 for posting pictures of your RAM Stacks, and tep392 for the detailed info about how the stack works, and the tip about connecting pins 14 & 15 instead of running the 2nd wire across the chip. I actually just used the pin I snipped off to place across 14 & 15. And yes I still have to snip off the pin in the top pic, but it works, and looks nice! :thumbsup:

 

Now I can make a few more. :grin:

post-53052-0-64238400-1524202509_thumb.jpg

post-53052-0-39931400-1524202518_thumb.jpg

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