exxos's Atari, Amiga & retro forum

Posted: **Thu Feb 21, 2019 8:18 pm**

Its only a simple transistor buffer type circuit which merges V & H.

: 1.jpg (55.67 KiB) Viewed 4899 times

NOTE that is from a "ST" so part numbers are likely different on your board, but the circuit will be the same.

Posted: **Thu Feb 21, 2019 8:39 pm**

Thanks this is perfect!

Looks like I need...

ST Location, Part, STF Location

Resistors (Need to follow traces to STF Location first):
R129, 10k, R49 (Brown, Black, Orange, Gold)
R130, 150, R50 (Brown, Green, Brown, Gold)
R131, 100, R51 (Brown, Black, Brown, Gold)

Transistor:
Q10, 2N3904, Q8

Diodes:
CR9, IN914, CR10
CR10, IN914, CR11

I have not studied electronics in ages, so thanks for the patience

exxos wrote: ↑Thu Feb 21, 2019 8:18 pm Its only a simple transistor buffer type circuit which merges V & H.

1.jpg

NOTE that is from a "ST" so part numbers are likely different on your board, but the circuit will be the same.

Posted: **Thu Feb 21, 2019 10:06 pm**

32bitminus wrote: ↑Thu Feb 21, 2019 6:49 pm

interesting, there is no BLiTTER's socket

Posted: **Thu Feb 21, 2019 10:09 pm**

I thought that was normal on the Blitter, bigger question for me, I know nothing about Mega STs, are the roms the same?

Posted: **Thu Feb 21, 2019 10:15 pm**

32bitminus wrote: ↑Thu Feb 21, 2019 10:09 pm I thought that was normal on the Blitter, bigger question for me, I know nothing about Mega STs, are the roms the same?

There is 6 chips and 2 chips TOS, All "ST" ranges have one or the other, generally TOS 1.00, 1.02, 1.04. They are all the same.

Posted: **Thu Feb 21, 2019 10:27 pm**

About to order parts, this looks like 1/4 Watt resistors would go in the composite sync circuit does anyone know if this is correct?

Posted: **Thu Feb 21, 2019 10:28 pm**

32bitminus wrote: ↑Thu Feb 21, 2019 10:27 pm About to order parts, this looks like 1/4 Watt resistors would go in the composite sync circuit does anyone know if this is correct?

All standard resistors yes.

Posted: **Thu Feb 21, 2019 10:36 pm**

32bitminus wrote: ↑Thu Feb 21, 2019 10:09 pm I thought that was normal on the Blitter, bigger question for me, I know nothing about Mega STs, are the roms the same?

I've got 3x 1040 STFs (all with red LEDs and with long button floppy drives) & none of them have the holes for the blitter (and they all have 6x ROMs under the PSU with the RAM under the keyboard and the processor under the floppy)...but all my STFMs (small floppy buttons) do have the holes for the blitter.

My STFs all came with TOS 1.00 but my STMFs all have at least 1.02 (and some have 1.04) and most (possibly all) are the 2 ROM versions.

AFAIK the TOS version is the same regardless of the number of ROMs or whether they came from an STF, a Mega ST or an STFM.

Posted: **Thu Feb 21, 2019 11:57 pm**

JezC wrote: ↑Thu Feb 21, 2019 10:36 pm
32bitminus wrote: ↑Thu Feb 21, 2019 10:09 pm I thought that was normal on the Blitter, bigger question for me, I know nothing about Mega STs, are the roms the same?
I've got 3x 1040 STFs (all with red LEDs and with long button floppy drives) & none of them have the holes for the blitter (and they all have 6x ROMs under the PSU with the RAM under the keyboard and the processor under the floppy)...but all my STFMs (small floppy buttons) do have the holes for the blitter.

My STFs all came with TOS 1.00 but my STMFs all have at least 1.02 (and some have 1.04) and most (possibly all) are the 2 ROM versions.

AFAIK the TOS version is the same regardless of the number of ROMs or whether they came from an STF, a Mega ST or an STFM.

Thanks! Figured as much, back in the day I had a 520STFM and that was my ST world, didn't know anyone else that had one.

Posted: **Thu Feb 21, 2019 11:58 pm**

exxos wrote: ↑Thu Feb 21, 2019 10:28 pm
32bitminus wrote: ↑Thu Feb 21, 2019 10:27 pm About to order parts, this looks like 1/4 Watt resistors would go in the composite sync circuit does anyone know if this is correct?
All standard resistors yes.

Thank you sir! Starting to build up my collection of standard components

exxos's Atari, Amiga & retro forum

Which 1040 STF is this?

Re: Which 1040 STF is this?

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Re: Which 1040 STF is this?

Re: Which 1040 STF is this?

Re: Which 1040 STF is this?

Re: Which 1040 STF is this?

Re: Which 1040 STF is this?

Re: Which 1040 STF is this?

Re: Which 1040 STF is this?