Microdrive Two Format Failure

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Vyper68
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Microdrive Two Format Failure

Postby Vyper68 » Thu Mar 12, 2020 4:43 pm

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 in MDV1 and then save a file on the cart using it in MDV2. I am assuming this problem stems from the Erase head but I'm not totally sure.
Any advice would be appreciated, I have my Gotek working now so I don't plan to open the QL up again until the QL ROM PCB turns up.


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bwinkel67
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Re: Microdrive Two Format Failure

Postby bwinkel67 » Thu Mar 12, 2020 5:02 pm

I have odd behavior with my two MDV's and after cleaning them they both worked a bit better (note that I very delicately oil the motor from the top and that has helped). Both can format but I feel MDV2 is a bit more flaky. I get certain cartridges that format and work on both and I've gotten some that format and read on only one (and it can be MDV1 or MDV2). MDV2 seems to be a bit pickier. One things I do sometimes is lift one end of the cartridge up and then I get better reading, so I think it's an alignment issue. This is usually more the case with MDV2 than MDV1 although if I have a cart that works on MDV2 and I stick it into MDV1 and lift the end it sometimes reads. Lifting might not be the right word, I basically try and torque it counter-clockwise with the thinking that the tape moves at a very, very slightly different angle over the head. I haven't mastered the best re-felting technique yet so I'm hoping that will alleviate some of this but I think even in the 90's I had a difference in performance for each (I must have even replaced one since I have a spare sitting in my file cabinet).

So all that being said it could be an alignment issue. I know there was a thread on how to align the head on MDVs and there was some sort of rig that was needed although the heads are kind of soldered in place so I wasn't quite sure what was meant.


Bytesguy
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Re: Microdrive Two Format Failure

Postby Bytesguy » Fri Mar 20, 2020 10:31 pm

Vyper68 wrote: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 in MDV1 and then save a file on the cart using it in MDV2. I am assuming this problem stems from the Erase head but I'm not totally sure.
Any advice would be appreciated, I have my Gotek working now so I don't plan to open the QL up again until the QL ROM PCB turns up.


Have you tried swapping the drives around? I just got a second QL and mdv1 (left) formats fine but mdv2 (right) fails. The strange thing is if I swap the drives over, then the left drive formats fine and the right one fails. I think there is something wrong on the main board somewhere....


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Vyper68
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Re: Microdrive Two Format Failure

Postby Vyper68 » Sat Mar 21, 2020 9:56 am

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.


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Bytesguy
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Re: Microdrive Two Format Failure

Postby Bytesguy » Thu Mar 26, 2020 12:08 am

Vyper68 wrote: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! Was it the signal test program you used?

I have some more info to share on the issue myself, I noticed that any drive that is designated as MDV1 works, regardless of which header it is plugged into on the board.

So for example, putting a drive in the right hand header (HBC2) and patching the comms in and comms out pins on the left hand header (HBC1) and using format mdv1_ works. Seems like as soon as drives are chained together that any drive downstream of the first one will fail formatting



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