Search found 69 matches

by tzok
Thu Sep 27, 2018 9:43 pm
Forum: ELECTRONICS
Topic: Desolder braid
Replies: 11
Views: 194

Re: Desolder braid

You should really forget about desoldering braid and desoldering pumps and get into the desoldering station, like ZD-915. Comfort of working with this is incomparable. For cleaning the pads you may still use the braid, together with RMA7 gel flux.
by tzok
Thu Sep 27, 2018 7:33 pm
Forum: HARDWARE ISSUES
Topic: 1040 STF showing occasional rogue pixels
Replies: 100
Views: 1431

Re: 1040 STF showing occasional rogue pixels

If it would be the MMU related problem, the stripes would be on a whole screen. As they are only on some region, it is more likely that the issue is with the RAM itself.
by tzok
Mon Sep 24, 2018 2:45 pm
Forum: SOFTWARE PROGRAMMING & DISCUSSION
Topic: Flying Shark level corruption on both FlashFloppy and HxC
Replies: 17
Views: 251

Re: Flying Shark level corruption on both FlashFloppy and HxC

In STeEM SSE you can choose between "fast" and "accurate" FDD emulation, so you may try on your own if timings do matter. Also STeEM SSE has a higher priority for games to run right than to accurately emulate the hardware.
by tzok
Sun Sep 23, 2018 11:34 am
Forum: HARDWARE ISSUES
Topic: resurrecting an STFM
Replies: 15
Views: 333

Re: resurrecting an STFM

The shifter is mounted normally (THT), the socket is soldered onto it. RAS/CAS resistors are disconnected, and +5V via additional resistor is fed into these lines to keep onboard RAM inactive.
by tzok
Fri Sep 21, 2018 8:37 pm
Forum: RTC (Real time clock)
Topic: Desoldering Falcon NVRAM
Replies: 11
Views: 1196

Re: Desoldering Falcon NVRAM

Working replacement chip is DS12887+, and I haven't found here information how to reset/initialize new chip, so:
Falcon 030: Alternate+Control+Right Shift+Undo
CT060: Control+Alternate+Undo
...during boot, before RAM test.
by tzok
Fri Sep 21, 2018 11:41 am
Forum: STF REMAKE PROJECT
Topic: 12V needed anymore ?
Replies: 6
Views: 289

Re: 12V needed anymore ?

There is a chance that UBEswitch will be fine with 5V on 12V rail... As for floppies - even the Sony FDD used on latter STes didn't use 12V.

The +/-12V has been used for RS232 only on early STs with external power adapter.
by tzok
Fri Sep 14, 2018 11:12 pm
Forum: RTC (Real time clock)
Topic: Desoldering Falcon NVRAM
Replies: 11
Views: 1196

Re: Desoldering Falcon NVRAM

As far as I know Falcon uses a standard DALLAS DS1287/DS1387 RTC or a compatible replacement. They are widely used in PC and some other equipment, like HP 5450x DSOs (actually there is a DS1235). There is a relatively easy hack to connect an external battery to this chip: http://www.mcamafia.de/mcap...
by tzok
Thu Sep 13, 2018 2:45 pm
Forum: RTC (Real time clock)
Topic: no-software internal RTC
Replies: 46
Views: 2707

Re: no-software internal RTC

I've experimentally measured the delay introduced by my ST IKBD RTC module:
SDS00048.png
SDS00048.png (164.6 KiB) Viewed 124 times
dT = 1.28ms
For comparison - screen redraw time in color mode is 20ms.
by tzok
Wed Sep 12, 2018 10:09 pm
Forum: PSU (power supplies)
Topic: PSU failure images
Replies: 2
Views: 547

Re: PSU failure images

The latter one is tricky to spot, as they have a dome-shaped plastic cover on top, so you never know if it's the capacitor "ready to explode" or just the cap looks like this.
by tzok
Wed Sep 12, 2018 10:03 pm
Forum: PSU (power supplies)
Topic: Replacement PSU for STf/STe
Replies: 0
Views: 74

Replacement PSU for STf/STe

I've managed to fit a MeanWell RT-65B PSU into the STf case in place of original PSU. It works fine on my "noisy" STf, even better (less noise) than my original STe PSU. This is a 65W switchmode PSU with 5V/5.0A, 12V/2.8A and -12V/0.5A. It barely fits the case. I had to remove its original aluminum ...