Re: Using ZX Microdrives on the QL
Posted: Fri Apr 21, 2017 1:49 pm
Tomas,
Sorry the ULA replacement comment was intended for my fourth 'faulty drive' that I cannot get to even recognise a cartridge - it just stops with microdrive not found (without restoring the ratchet or a new roller and plastic wheel of course it will never work as it has the dud roller swapped to it) - if you try and use it to format (with a roller restored) it stays white on the third stage which the service manual (para 3.2) says indicates "noise on the write line" from either motor alignment, ULA or regulator (The reg is producing 5.07v without ripple but maybe that is a bit high so perhaps I could swap that first - I had a spare ULA that seemed the best approach as I don't have a motor alignment jig - I am asking anyone I can find with engineering tools to make me one... It can also go into a hard lock of the tape spinning which is why I suspect maybe a ULA rather than the motor/regulator - if the amps are flawed then the signal will be noisy? I'm clutching at straws really as they are getting so rare and expensive it seems a share to write on off! I have not swapped electrolytics or polyester caps on this to act as a bit of control to work out what the actual fault is...
This is sort of the same but, worse than the symptoms I am getting on 04-083529 but, that does seem to get some sectors written although I have seen the format very low between 1 and 50 sectors only again it seems to be more white on the third stage of the format. It is this one that I have swapped the two electrolytics and the polyesters which gave a much cleaner signal on the scope during the read of a formatted cartridge and got it at least going to read data written on other cartridges. (The reg on that reads 4.99v no ripple). Again this supports the noise on the write line theory. I.e. it can read but, written data is unreliable.
I did the resister swap for the QL test as it does read cartridges so I could at least see if that was helped but, it didn't - of course format would never work as it doesn't on the Spectrum!
I tried to look for my walkman to check the head but, it occurred to me that it was play only so there would be no erase head - and all my old tape units have a separate erase head.
Timbucus.
Sorry the ULA replacement comment was intended for my fourth 'faulty drive' that I cannot get to even recognise a cartridge - it just stops with microdrive not found (without restoring the ratchet or a new roller and plastic wheel of course it will never work as it has the dud roller swapped to it) - if you try and use it to format (with a roller restored) it stays white on the third stage which the service manual (para 3.2) says indicates "noise on the write line" from either motor alignment, ULA or regulator (The reg is producing 5.07v without ripple but maybe that is a bit high so perhaps I could swap that first - I had a spare ULA that seemed the best approach as I don't have a motor alignment jig - I am asking anyone I can find with engineering tools to make me one... It can also go into a hard lock of the tape spinning which is why I suspect maybe a ULA rather than the motor/regulator - if the amps are flawed then the signal will be noisy? I'm clutching at straws really as they are getting so rare and expensive it seems a share to write on off! I have not swapped electrolytics or polyester caps on this to act as a bit of control to work out what the actual fault is...
This is sort of the same but, worse than the symptoms I am getting on 04-083529 but, that does seem to get some sectors written although I have seen the format very low between 1 and 50 sectors only again it seems to be more white on the third stage of the format. It is this one that I have swapped the two electrolytics and the polyesters which gave a much cleaner signal on the scope during the read of a formatted cartridge and got it at least going to read data written on other cartridges. (The reg on that reads 4.99v no ripple). Again this supports the noise on the write line theory. I.e. it can read but, written data is unreliable.
I did the resister swap for the QL test as it does read cartridges so I could at least see if that was helped but, it didn't - of course format would never work as it doesn't on the Spectrum!
I tried to look for my walkman to check the head but, it occurred to me that it was play only so there would be no erase head - and all my old tape units have a separate erase head.
Timbucus.