Hi Al
Many programmers use the +5V to switching boost for programming voltage because the needed
level has a low current load for the programming level. The additional wire might be for a
negative level, such as RS-232 or DRAM. These are still things that can be traced out with
and ohm meter and also look for polarized capacitors. If there is RS-232, look for the
drivers. Maxim parts use built in capacitive charge pumps and don't need a negative
rail. These are all good indicators of what the levels are.
PAL programmers need higher programming current than EPROMs.
I don't know the particular programmer's purpose you have.
Dwight
________________________________
From: cctalk <cctalk-bounces at classiccmp.org> on behalf of Al Kossow via cctalk
<cctalk at classiccmp.org>
Sent: Tuesday, September 15, 2020 8:38 AM
To: General Discussion: On-Topic and Off-Topic Posts <cctalk at classiccmp.org>
Subject: Re: ISO Advantech Labtool-148C prgrammer wall wart specs
On 9/15/20 7:39 AM, dwight wrote:
It may be low voltage AC and ground or it may be +5V
and a high voltage for programming and a return ground. You might look inside to see
what the wires lead to.
it is two DC voltages. I haven't traced out which one is 5v