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by exxos
Mon Sep 17, 2018 2:51 pm
Forum: PSU (power supplies)
Topic: Discharging capacitors, PSU-testing with dummy loads
Replies: 33
Views: 3535

Re: Discharging capacitors, PSU-testing with dummy loads

Okay, so it'll mostly protect itself. I shouldn't expect blown caps if I do a bodge job and miss something. Also, the PSU will discharge the caps over a short period by itself, right? I would check the 400V caps with voltage on meter to make sure its safe. Bad caps can cause spikes in the voltage, ...
by exxos
Mon Sep 17, 2018 2:35 pm
Forum: PSU (power supplies)
Topic: Discharging capacitors, PSU-testing with dummy loads
Replies: 33
Views: 3535

Re: Discharging capacitors, PSU-testing with dummy loads

Far as I can tell, the PSU is handing out 3.5V on the 5V lines, and 9V on the 12V lines. But I want to measure properly, and I'm going to load test with the resistors for sale in the store. The PSU will malfunction without a lot. So that I'm sure I'm measuring the correct thing, and following Pacma...
by exxos
Mon Sep 17, 2018 12:58 pm
Forum: RTC (Real time clock)
Topic: FALCON 030 RTC (2017 Batch)
Replies: 27
Views: 3205

Re: FALCON 030 RTC (2017 Batch)

The only time I have issues updating the Exxos NVRAM is when I use the utility bootc201.zip by Uwe Seimet. After using that my Falcon boots to a black screen without fail. Popping the battery out of the NVRAM before powering back on after a few seconds often resolves this. Thanks for letting us kno...
by exxos
Mon Sep 17, 2018 12:31 pm
Forum: STF REMAKE PROJECT
Topic: PSU bracket remake ?
Replies: 65
Views: 1898

Re: PSU bracket remake ?

On a side note, I just realised (while reading http://www.exxoshost.co.uk/atari/last/tos/index.htm, halfway the page) that the printed bracket - without the mesh - could actually make some upgrades fit under the PSU that currently don't, such as some TOS upgrade kits for mainboards that have the TO...
by exxos
Mon Sep 17, 2018 12:29 pm
Forum: CHAT FORUM
Topic: competent repair people ?
Replies: 28
Views: 1133

Re: competent repair people ?

So how does that go, you diagnose it, write down a note saying replace this this and this, fix this broken trace here, and stick it all with the new parts in a box and hand it over? I have done the diagnostics, they do the repairs. But since a lot is RTC replacement, any good soldering company can ...
by exxos
Mon Sep 17, 2018 12:10 am
Forum: STF REMAKE PROJECT
Topic: ALPHA MODIFICATIONS
Replies: 85
Views: 2664

Re: ALPHA MODIFICATIONS

After cutting the trace on both sides of R920 ,,,, measure between D7 and the cut free R920 i get zero ohm, those two point must go to positive plane in pcb, so i guess no need to move the R920. ahh yep, The left link wire isn't needed as the resistor itself actually connects to vcc.. will update t...
by exxos
Sun Sep 16, 2018 10:30 pm
Forum: STF REMAKE PROJECT
Topic: ALPHA MODIFICATIONS
Replies: 85
Views: 2664

Re: ALPHA MODIFICATIONS

HSYNC FIX

from here viewtopic.php?f=19&t=1146&start=90#p9961

I ballsed up the Hsync and it needs a fix to bypass the inverter...

d1.JPG
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by exxos
Sun Sep 16, 2018 10:20 pm
Forum: STF REMAKE PROJECT
Topic: PCB Build - Progress - Post your Pics here :-)
Replies: 135
Views: 4435

Re: PCB Build - Progress - Post your Pics here :-)

So I obviously got confused with those 3 Hsync lines :(

The fix is simple to do.. Lift pin 8 out of the socket on the LS04 U51 (or cut it off) .. and wire link on the bottom of the socket pins 8 & 9... so that will bypass that inverter...
d1.JPG
d1.JPG (49.49 KiB) Viewed 206 times
by exxos
Sun Sep 16, 2018 10:08 pm
Forum: STF REMAKE PROJECT
Topic: PCB Build - Progress - Post your Pics here :-)
Replies: 135
Views: 4435

Re: PCB Build - Progress - Post your Pics here :-)

Just got home and looking at Hsync I have it inverted... On the original ST diagram it goes though a inverter to a LS74.. on the STF the inverter isn't even there ... So I think Hsync is actually wrong and its inverted when it shouldn't be :roll: .. I will do some more checking... EDIT: hmm.... Its ...
by exxos
Sun Sep 16, 2018 9:40 pm
Forum: HARDWARE DISCUSSIONS
Topic: Project: HDMI/DVI out for STFM
Replies: 262
Views: 16963

Re: Project: HDMI/DVI out for STFM

(... and this is where my own knowledge is a bit lacking, but I have seen this described as the Shifter "owning" that register, as in, holding its contents and being responsible for outputting that data when that memory address is accessed) I half recall it was a shadow register in the shifter ?, w...