Search found 260 matches

by tzok
Fri Apr 02, 2021 4:12 pm
Forum: 8 BIT CORNER
Topic: 800xl power supply - how to open?
Replies: 3
Views: 3212

Re: 800xl power supply - how to open?

I have drilled a hole from top to help to remove the resin block from the inside. Then I've put a LED in that hole ;)
by tzok
Fri Mar 12, 2021 4:46 pm
Forum: HARDWARE ISSUES
Topic: 1040 STE no sound....quest accepted
Replies: 7
Views: 2656

Re: 1040 STE no sound....quest accepted

Q500 is not a transistor, but a voltage regulator. If it has 12V on the input, proper GND, and nothing on the output, then something shorts its output to ground. Sound Hardware seems to be recognized correctly - value of 3 indicates, both Yamaha and DMA are present, so the problem is likely in the a...
by tzok
Tue Mar 02, 2021 8:15 am
Forum: STE V1 SERIES 32MHz BOOSTER
Topic: STE 32MHz PLUG IN BOOSTER (again) 2021 variation
Replies: 95
Views: 38238

Re: STE 32MHz PLUG IN BOOSTER (again) 2021 variation

For FDD most lines there are open collector with pull-ups, so adding capacitance parallel to the ground creates a nice low pass filter.
by tzok
Mon Mar 01, 2021 6:28 pm
Forum: STE V1 SERIES 32MHz BOOSTER
Topic: STE 32MHz PLUG IN BOOSTER (again) 2021 variation
Replies: 95
Views: 38238

Re: STE 32MHz PLUG IN BOOSTER (again) 2021 variation

HigashiJun wrote: Mon Mar 01, 2021 1:34 pm Even if the rivet is overlapping the track, it does not go under the PCB coating - but is just laying on it - and is then perfectly insulated from the copper layer.
I'm not suggesting shorts, but measure the capacitance. You're basically adding a few dozen pF between GND and each line.
by tzok
Mon Mar 01, 2021 11:50 am
Forum: STE V1 SERIES 32MHz BOOSTER
Topic: STE 32MHz PLUG IN BOOSTER (again) 2021 variation
Replies: 95
Views: 38238

Re: STE 32MHz PLUG IN BOOSTER (again) 2021 variation

It looks nice, but I'm afraid, these areas may cause problems:
Clipboard-1.jpg
Clipboard-1.jpg (410.24 KiB) Viewed 3978 times
by tzok
Sun Feb 21, 2021 8:41 pm
Forum: ELECTRONICS
Topic: Why are rechargeable AA/AAA batteries 1.2v not 1.5?
Replies: 4
Views: 2720

Re: Why are rechargeable AA/AAA batteries 1.2v not 1.5?

Terms "battery" and "cell" are often used interchangeably, however the cell is a single unit, which voltage is denominated by chemistry used inside. While a battery may be build from one or more cells (to be technically precise from two or more cells), and its voltage is a multip...
by tzok
Sun Feb 14, 2021 1:21 pm
Forum: HARDWARE DISCUSSIONS
Topic: what can be safely removed from STfm
Replies: 11
Views: 4654

Re: what can be safely removed from STfm

Atari SM/SC monitors use H/V sync, same is for VGA monitors, but some 3rd party RGB monitors and SCART equipped TVs require a composite sync. Also Chinese upscalers like GBS8200 and SCART-HDMI converters need it.
by tzok
Sun Feb 14, 2021 11:19 am
Forum: HARDWARE DISCUSSIONS
Topic: what can be safely removed from STfm
Replies: 11
Views: 4654

Re: what can be safely removed from STfm

On the STf it seems that you have to solder in some components if you want to have composite out. I'm afraid this will produce only the composite sync signal (required for SCART RGB), not the composite video. Yet RGB SCART requires composites sync, not composite video (which may be used for this pu...
by tzok
Tue Feb 09, 2021 11:18 am
Forum: HARDWARE ISSUES
Topic: STFM RAM Diagnostics
Replies: 11
Views: 3862

Re: STFM RAM Diagnostics

If you have an oscilloscope, try to observe address lines and Din/Dout lines of DRAM chips while rebooting the system. Look for lines that are always high or always low, or never reach the right voltage levels.If a chip is faulty it may short Din/out (D/Q), or its address lines to GND or Vcc, and th...
by tzok
Wed Feb 03, 2021 9:59 am
Forum: MEMBER BLOGS
Topic: Paradroid STE DMA issue blog
Replies: 72
Views: 26747

Re: Paradroid STE DMA issue blog

I've also found the ACSI cable to be extremely important to the reliability of 3rd party ACSI devices. 20 cm ribbon cable seem to be more or less a maximal length. Also, the crappy fake Apple/Samsung USB chargers often bundled with various 3rd party devices are causing problems. Use a good quality P...

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