The Sinclair QL Forum

Hi, I have removed my QL regulator and heat sink and replaced it with the Tetroid Power Regulator replacement board: https://www.sellmyretro.com/offer/details/sinclair-ql-power-module-%28-7805-replacement-%29-28469 The QL is running ultra cool, even with a Super Gold Card fitted. Interesting! I hav...

I seem to have possibly cured the other QL by pulling out the TSR 2450 regulator and reverting back to a (new) 7805. After replacing it seems MDV1 is back to fully working and MDV2 does format most times but occasionally fails to - good enough for me!! I’ll do some more testing later on to confirm ...

Hi Bytesguy! Well, that was something of an adventure, wasn't it! Some of those switching regulator replacements can certainly be noisy and, given the closer proximity to the MDV in slot#2 versus slot#1, coupled with (typically) the MDV in slot#1 having a simple shield around the ULA, the end resul...

a Evening! So the diodes were D17 D28 and D16. I also replaced TR3 TT4, TR5, TR6 and TR7. Some of those are for MDV2 so may not apply to you but probably won’t harm to replace them! I’m still baffled why my other QL is wonky but I may just give up on it for now! Hi, Are you able to measure the comp...

Hello Byteguy, Thank you for all this information, which is going to help me in fxing mine. My MDV1_ just spins. MDV2_ is fine. I have swapped them around and bought two new old stock drives. All four of them work, but not in the MDV1_ slot. :( My next step was to replace the ZX8302, which is curre...

Wanted to post an update here! I renewed all the transistors and diodes which are involved in the microdrive operations and now I have a fully working QL! Both drives format fine, though MDV2 is a little on the slower side (not always a bad thing). I did the same on my other QL but unfortunately it ...

I was able to get MDV2_ to format once after I used the test program from the service manual but hasn’t worked since. That said I have a Kempston disk Interface so i won’t be using them much now. I was just thinking if there was any hardware fix like replacing the Regulator. That's really strange! ...

Hi I kind of have 1 & 1/2 working Microdrives. I know there is another thread talking about microdrive format issues but I didn't want to hijack it with my problem, not that it's a major one. MDV1 will Read/Write and Format and MDV2 will Read/Write but will not Format. I can format a cartridge ...

Hi Bytesguy! In addition to my PM of earlier today, I'd recommend you testing one of the suspect MDV units in the position of MDV#1 of the second QL. It is highly unlikely to cause damage to the QL, and would quickly confirm whether or not the first QL mainboard was contributing to the MDV format f...

I'm back with an update! So I have replaced the CPU, ZX8301, ZX 8302 and the 8049 and TR3 all with no luck, still getting format failed. I have ordered a couple of microdrive ULAs from Rich so I will try and replace those when they arrive and see how it goes! Meanwhile, I have acquired a second QL. ...