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Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: LoadWB on October 06, 2007, 02:46:16 AM

Title: A500 does not reset on C-A-A
Post by: LoadWB on October 06, 2007, 02:46:16 AM

I have two A500s here that will not reset when pressing CTRL-Amiga-Amiga.  Nothing else seems to be affected -- no other keys are bad or stuck, and each key works properly independently.  Any ideas?

Title: Re: A500 does not reset on C-A-A
Post by: steve30 on October 06, 2007, 09:49:44 AM

Quote

and each key works properly independently.

Do you mean that the CTRL and Amiga keys work properly when using the Amiga?

My A500+ also does not reset with CTRL+A+A, but upon testing it, Neither the CTRL, Amiga, ALT or SHIFT keys work when using the Amiga, which suggests a faulty keyboard.

Title: Re: A500 does not reset on C-A-A
Post by: Zac67 on October 06, 2007, 11:50:13 AM

Two possibilities: either one of the C-A-A keys is broken or the _KBRESET line from the keyboard is.

Title: Re: A500 does not reset on C-A-A
Post by: Lockon_15 on October 06, 2007, 04:36:30 PM

Or maybe one of 2 transistors on keyboard PCB is gone for good...

Title: Re: A500 does not reset on C-A-A
Post by: LoadWB on October 06, 2007, 05:24:06 PM

Quote

Lockon_15 wrote:
Or maybe one of 2 transistors on keyboard PCB is gone for good...

Anyone have a schematic of the A500 keyboard?  I don't think there's one in the manual.

Title: Re: A500 does not reset on C-A-A
Post by: taunusand on October 07, 2007, 01:57:46 AM

In my A500 manual (danish) there is a diagram.

But here are the pinout:
1: Clock
2: Data
3: Reset
4: +5Volt
5: nc (No connection)
6: Gnd
7: Power led
8: Disk activity led

Maybe something with in 5 is the problem?

Title: Re: A500 does not reset on C-A-A
Post by: amigaksi on October 07, 2007, 06:01:37 AM

>Anyone have a schematic of the A500 keyboard? I don't think there's one in the manual

There are schematics in the "Introduction to Amiga 500" manual (some introduction).  In the version that I have the keyboard pins 1 and 2 are reversed (found out the hard way-- experimentally).  However, the reset and ground pins were correctly labelled.  Try connecting the reset to the ground pin (carefully) and if that resets the Amiga, you know it's the keyboard and not the motherboard.  Or if not technically inclined, try the Peripheral Simulator here:

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=320167447376

If it works and allows you to reset your Amiga from the PC, it's not the reset line on your motherboard.

Title: Re: A500 does not reset on C-A-A
Post by: Speelgoedmannetje on October 08, 2007, 04:12:39 PM

Quote

Zac67 wrote:
Two possibilities: either one of the C-A-A keys is broken or the _KBRESET line from the keyboard is.

There is no _KBRESET line on any type of keyboard I have ever seen. :-?
Only keyboard data, clock, ground and +5v.
Isn't it some option in the OS/kickstart that has disabled this?

Title: Re: A500 does not reset on C-A-A
Post by: Zac67 on October 08, 2007, 06:41:31 PM

(http://wowohl.de/Pix/A500kbd.gif)
 :roll:

Title: Re: A500 does not reset on C-A-A
Post by: amigaksi on October 13, 2007, 07:45:45 AM

Should be clock (_KBCLOCK) on pin 1 and data (_KBDATA) on pin 2 instead of what the Introduction to Amiga 500 Manual schematic states (in Appendix F).

Title: Re: A500 does not reset on C-A-A
Post by: CLS2086 on October 13, 2007, 11:08:05 AM

Hi,
try also to disassemble your keyboard and use electronic spray cleaned on the transfert film.