18 Jun
2011
18 Jun
'11
3 p.m.
----- Original Message -----
From: "Terry Stewart" <terry at webweavers.co.nz>
To: "General Discussion: On-Topic and Off-Topic Posts"
<cctalk at classiccmp.org>
Sent: Saturday, June 18, 2011 11:12 AM
Subject: Re: More Sorcerer musings. Cassette interface issue,or a MESS
programming issue?
Well, I've spent a few hours today playing with my Dual Powered Standard
Willem ROM burner.
It seems reasonably straightforward. I've managed to read the contents of a
few 27C256 EPROMS successfully. However, I couldn't read the contents of
the BASIC-PAC 2k masked ROMS? I'm sure I have all the jumpers and switches
right for a 2716, which I understand is an equivalant EPROM chip . All I
got from all the ROMS was a repeating pattern of 0406 for 256 bytes then
1416 for the next 256 bytes and so on.
I've checked and rechecked the settings and they seem right? Thinking I
might have damaged the original ROMs by trying to read them I re-checked
them again in the Sorcerer monitor. The data was still intact, except for
the faulty ROM 3, which as before showed all zeros.
I did read on a website somewhere that some masked ROMS could not be read by
some EPROM programmers. Do you think that's the case here?
I won't be able to burn any 27C16s to fix the ROM-PAC until the chips arrive
in the post it's a waiting game for now.
Terry
The burner
will almost certainly have a read mode. If it were me, and I
realize this is sort of belt and suspenders thinking, I would read and
display the suspected bad EPROM contents using the burner. You will
likely see the same results, but it should definitely confirm (or
question) your original very fine analysis.
Later,
Charlie C.
Yes, I will do that Charlie.