Search found 903 matches

by martyn_hill
Tue Dec 05, 2017 4:49 pm
Forum: Hardware
Topic: Microdrive Unit Design
Replies: 118
Views: 52097

Re: Microdrive Unit Design

Thanks Big-D! Sources: Remove the MC1377 and use other video output ;) I typically use the RBGVH lines (via SCART), so I guess I can safely remove the noisy MC1377, right? Add a large electrolytic cap across +5v and GND on the 8301, two places in DRAM, 8049, and near J1 By 'large', is that in the 22...
by martyn_hill
Tue Dec 05, 2017 11:16 am
Forum: Hardware
Topic: Microdrive Unit Design
Replies: 118
Views: 52097

Re: Microdrive Unit Design

A lot of noise is induced into the cable connecting it to the QL, but it's small compared to the signal. Hi Dave - were you referring in this line to the 2x 7-way cables connecting the MDV to the mainboard, or to the voltage reg 3-way connector? However, a lot is also induced into the head itself, ...
by martyn_hill
Tue Dec 05, 2017 11:10 am
Forum: Hardware
Topic: QL ROM switcher
Replies: 29
Views: 15338

Re: QL ROM switcher

The external switch is a terrific idea - well done, Vitaliy!
by martyn_hill
Tue Dec 05, 2017 11:08 am
Forum: Hardware
Topic: Q68 Order Process
Replies: 344
Views: 174508

Re: Q68 Order Process

Mine arrived safely several days before expected - carefully packaged and that case! Very professionally engineered and finished! Just need some time to play, now - thanks Peter, Derek and Wolfgang (who, I understand worked a lot on the SMSQ/E side.) In due course, I intend to explore the developmen...
by martyn_hill
Mon Dec 04, 2017 12:23 pm
Forum: Hardware
Topic: Microdrive Unit Design
Replies: 118
Views: 52097

Re: Microdrive Unit Design

Hi Tobias That is encouraging - when I recently ordered a couple of replacement ULAs from Rich M, I was pleasantly surprised to note that they were brand-new, with 85xx batch markings - I had been expected desoldered ICs from old MDVs - silly me! Of course its not the most trivial desolder/resolder ...
by martyn_hill
Mon Dec 04, 2017 10:49 am
Forum: Hardware
Topic: Microdrive Unit Design
Replies: 118
Views: 52097

Re: Microdrive Unit Design

Hi Tomas I have recently been able to carry out quite a range of empirical tests on a diverse set of MDV units of different vintage, ranging from the unmarked models that we have decide to term 'Iss#5', through the explicitly marked Iss#6 and Iss#7. To be honest, I have not yet found a strong correl...
by martyn_hill
Sun Dec 03, 2017 3:45 pm
Forum: Hardware
Topic: Microdrive Unit Design
Replies: 118
Views: 52097

Re: Microdrive Unit Design

Thank you very much Charles - that clears-up the question of encoding!
by martyn_hill
Wed Nov 29, 2017 4:51 pm
Forum: Hardware
Topic: ULA ZX8301 - TV Picture Capabilities
Replies: 62
Views: 31331

Re: ULA ZX8301 - TV Picture Capabilities

Darn - you beat me too it!

Gota love Nasta!
by martyn_hill
Wed Nov 29, 2017 4:31 pm
Forum: Hardware
Topic: ULA ZX8301 - TV Picture Capabilities
Replies: 62
Views: 31331

Re: ULA ZX8301 - TV Picture Capabilities

Can't wait for the next gripping episode!

(Do we get a prize if we answer the A6 question correctly?) :-)
by martyn_hill
Tue Nov 28, 2017 10:55 pm
Forum: Hardware
Topic: Q68 Order Process
Replies: 344
Views: 174508

Re: Q68 Order Process

Well done, Derek!