Recent content by BennehBoy

I guess it depends what you wish to use it in, they work just fine in 1541's. But yeah 6522 equiv, not 6526 as I wrote - braino moment.

6526 is available as brand new part still -> https://www.mouser.co.uk/ProductDetail/Western-Design-Center-WDC/W65C22N6TPG-14?qs=opBjA1TV901DbgJ9rfcBoQ%3D%3D&countrycode=GB&currencycode=GBP

Are you able to update the firmware on the older pi1541?

Excellent, glad you got it fixed.

I'm by no means an expert but I think I'd be targeting UF3.

You could work outward from UC1, there's a data in pin where a serial stream comes in from the read head, it's get's differentially amplified by the 2 592's and then more so by the 311. UC1 then essentially deserialises the data stream and pops it out 8 bits at a time to UC2. I'm not sure...

Got to be worth trying to replace the trimmer pot or the newtronics control board first - there are a lot of drives out there with dead heads so I would've thought it may not be too hard to obtain. I don't know the pot value I'm afraid. I had an alps with a very slower spindle motor, but it...

If the head resistances check out then Frank's post above is spot on for the parts that could be at fault, it's scope time, or substitution with known good parts to address. Similar issues I've seen on 2 Alps drives were a failed gate array in one instance, and failed 592 in the other.

Mechboard64 is the only replacement that I'm aware of, it aint cheap.

Resistances should be as per the service manual: https://www.classic-computing.org/wp-content/uploads/2016/01/15401541_SERVICE-MANUAL.pdf Extract here: There's a reasonable troubleshooting guide in there, but I tend to use Ray Carlson's chip fault finding guide from here ...

Further to this, I managed to source a spare spindle motor. I fitted this which fixed the slow motor issue, but although I could load a disk directory (slowly), no larger programs would load successfully. Given that a directory was working, clearly this was not a logic issue, but rather a...

Looks correct to me. Have you checked the resistances of the r/w heads? It's uncommon for Alps heads to fail but certainly worth doing. Also, it may be that some of the circuitry has become inadvertently damaged, UC1 plays a big part in controlling the movement of the stepper motor (as does...

Last update on this, I fixed the alignment issue - I had to elongate the adjustment slots on the stepper motor. I guess the motor is tired or the spindle has rotated in the headstop attachment. All good now, and I've managed to source a replacement spindle motor for the other drive with the...

So.... I have removed the mechanism from DRIVE1 and transplanted it into DRIVE3, for some reason the mechanism reads more disks when hooked up to the newer revision PCB in there - no clue why. BUT, alignment when I check it against a few factory disks now has every track off by 1. There are...

Thanks for the explanation. I used a 'user' disk that came with one of the drives - I have some CBM factory created disks which I'll try torquemada against instead.