Prev: C64-emulator for Linux
Next: 64HDD Celebrates 10years
From: Mino on 12 Aug 2010 18:21
I've been looking at barely readable schematics all day long but still
can't figure it out. I need the value of R11 on the 1541 drive's
motherboard, assy # 250442. My board is _exactly_ like this one:
http://snipurl.com/10lq4q
If you look around the IC in position UD4 (it's a 74123), you'll
notice that:
- C31 is not installed
- R12 (just below the chip) is 24 KOhm (red, yellow, orange, gold)
R11 is just above the 74123. Unfortunately, its colors aren't clearly
distinguishable.

The schematics I saw don't match, despite being labelled "assy
250442". On page 31 of this document http://snipurl.com/10lqih it's
written that UD4 can be either a 9602 or a 74123 and R12 must be
either 22 KOhm or 15 KOhm respectively. I had a look inside another
1541 with the same PCB. There is a 74123, R12 is 15 KOhm and R11 is
5.1 KOhm, so maybe I can use these 2 values.

Anyway, if anyone has a PCB like the one in the first picture (UD4 =
74123 and R12 = red, yellow, orange, gold) please tell me the value of
R11!

From: Mino on 13 Aug 2010 05:02
Bryan <bry(a)net.net> wrote:

>On mine... green, brown, red, gold .. 5.1K 5%
Thank you very much for disassembling the drive for me! By the way,
did you also check R12?
From: u on 13 Aug 2010 09:03
On Thu, 12 Aug 2010 22:21:09 +0000, Mino wrote:

> I need the value of R11 on the 1541 drive's
> motherboard, assy # 250442.

> Anyway, if anyone has a PCB like the one in the first picture (UD4 =
> 74123 and R12 = red, yellow, orange, gold) please tell me the value of
> R11!

On my 250442 board UD4 is 74LS123, R12 is 15k (brown, green, orange,
gold) and R11 is 5.1k (green, brown, red, gold).

From: Mino on 13 Aug 2010 11:51
u <1541(a)kotinet.com.sotku> wrote:

> On my 250442 board UD4 is 74LS123, R12 is 15k (brown, green, orange,
>gold) and R11 is 5.1k (green, brown, red, gold).

Thank "u"!! :)

 | 
Pages: 1
Prev: C64-emulator for Linux
Next: 64HDD Celebrates 10years