I bought a no error codes on startup S/N B057443. Inspection of A5 showed no leaking of the SMD eCaps, but the Dallas DS1225Y was 1991 vintage by date code. I bought a new Dallas DS1225AB-200+ from Mouser. Desoldered the old SRAM with a Hakko 472D uneventfully, placed a TE Connectivity 1-2199299-2 28P DIP SKT 600 CL LADDER socket and soldered it in place without drama. Good looking solder joints. I was able to read the 1991 DS1225Y with the GQ-4x4 programmer and saved the data to a .bin file. I wrote and verified the .bin file to the 2023 ¡°new¡± DS1225AB-200+ SRAM. Placed it carefully and correctly into the sock, and now have the 04 Fail error. Same thing with the old 1991 SRAM.
I read the old and new SRAM data sets after trying startup, both sets of data were significantly changed. Bad solder joints?
I ohm-checked the SRAM socket pins to the A5 board connections, listed below. The lowest resistance I found was a few .02¦¸, most common was about .2¦¸ and the highest was .53¦¸. Seems higher than I¡¯d like in general. Normal?
Tek 2465B Late A5 U2460 Pin Connections
U2460
Pin Descriptor Component Pin
1 U2250 15
2 BA12 U2160 3
3 BA7 " 4
4 BA6 " 5
5 BA5 " 6
6 BA4 " 7
7 BA3 " 8
8 BA2 " 9
9 BA1 " 10
10 BA0 " 11
11 BD0 J4241 29
12 BD1 " 27
13 BD2 " 25
14 - " -
15 BD3 " 23
16 BD4 " 28
17 BD5 " 24
18 BD6 " 22
19 BD7 " 20
20 U2250 11
21 BA10 U2160 24
22 " 25
23 BA11 " 27
24 BA9 " 28
25 BA8 " 29
26 U2250 19
27 J512 23
I¡¯m at a loss what to do going forward. Any help would be appreciated.
Thanks, Ron
AF5IV
