Products > Test Equipment
Just got a Tek 2465A, couple questions (how I screwed the calibration data)!!
tggzzz:
--- Quote from: linux-works on March 27, 2018, 02:50:58 pm ---
--- Quote from: tggzzz on March 27, 2018, 01:47:56 pm ---
That doesn't change the basic point that the "my time is more valuable than your time" attitude is very irritating for many people.
--- End quote ---
I just don't see it that way and we'll have to disagree and leave it at that.
--- End quote ---
I doubt we will agree, but others do share my weltanschauung - including some in this thread!
--- Quote ---... and tell them to RTFM (which is really what you are saying).
--- End quote ---
No, that is not what I am saying.
I am saying that if you know what you could do but can't be bothered to do the legwork, what make you think we can be bothered to do legwork helping you?
MarkL:
--- Quote from: alpher on March 27, 2018, 05:03:10 pm ---...
Here you can see it attached by soldered ! leads to one of the standoff grounds and cathode of CR2770 . There is also an 1N4007 in series with the positive lead ( just in case) .
...
--- End quote ---
Are you sure that screw pad you soldered to is connected to the ground of the board? Some of those pads could be floating.
alpher:
When I saw what I've done was quite upset >:(, so much so that I let it sit for a couple of weeks or so.
You must know that this is a purelly hobby for me, and not only I lack the equipment necessary to calibrate such a scope but probably also skills to do it. :(
Then I came up with an idea that if the sram got scrambled by me momentarily shorteing somehow the vcc pin during the whole procedure it may be scrambled only by a couple of bits or so and by reading it I may be able to figure out what was there originally.
Rigged something like this:
Read the memory no problems at all, actually I read it mor than 10 times switching on/off between the reads changing settings ETC.
Just to have a general feeling what's going on inside. Found out that the las 512 bytes or so never change and probably there the cal constants are stored.
When I figure out how to properly paste HEX data I'll post the listing.
T.B.C.
alpher:
OK, here's the last 512 bytes of the SRAM:
--- Code: ---Offset(h) 00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F
00001E00 EF 22 00 FD FE 02 85 FA 7F A0 04 DE EB 80 00 7F ï".ýþ.…ú. .Þë€..
00001E10 7F 04 41 DF 9F 02 10 BD 15 A0 04 BF D5 88 00 DF ..Aߟ..½. .¿Õˆ.ß
00001E20 FD 20 00 FD FF 34 13 7B BE 84 48 FB 7D 00 01 FD ý .ýÿ4.{¾„Hû}..ý
00001E30 F2 C0 40 EF FF 03 40 D9 FB 00 02 BB 7D 00 04 9F òÀ@ïÿ.@Ùû..»}..Ÿ
00001E40 BE 90 90 F7 FB 08 83 3F 9F 40 0C FF BF 00 88 FF ¾..÷û.ƒ?Ÿ@.ÿ¿.ˆÿ
00001E50 FF 08 22 EF FF 42 42 AF 5F 01 00 59 FF 0A 40 F6 ÿ."ïÿBB¯_..Yÿ.@ö
00001E60 BF 0A 24 FD 7F 18 28 B7 FE 84 80 FF 7F 00 40 FF ¿.$ý..(·þ„€ÿ..@ÿ
00001E70 FB 18 00 4F 97 13 02 BF FA 8A 23 FF F7 02 05 F7 û..O—..¿úŠ#ÿ÷..÷
00001E80 D7 00 61 7F DD 01 88 B7 3C 20 21 FE DD 01 A8 FF ×.a.Ý.ˆ·< !þÝ.¨ÿ
00001E90 BF A1 00 BA FF 40 48 3F FF 04 00 9B DF E1 92 FB ¿¡.ºÿ@H?ÿ..›ßá’û
00001EA0 FF 00 06 7F FD C4 20 FD FE 26 10 79 FE 32 84 8F ÿ...ýÄ ýþ&.yþ2„.
00001EB0 EB 00 30 FF EE 00 05 7F DF 80 81 B7 BD CA 40 DF ë.0ÿî...߀.·½Ê@ß
00001EC0 AE 26 04 D7 F6 06 82 F7 76 10 02 DC F7 E1 10 7F ®&.×ö.‚÷v..Ü÷á..
00001ED0 DD 31 04 EB D7 2A 41 FB DE 06 20 DD BE 00 20 7F Ý1.ë×*AûÞ. ݾ. .
00001EE0 FD 01 14 F5 7F 04 60 FF FF 90 0C FF EE 80 8C BF ý..õ..`ÿÿ..ÿ¿
00001EF0 DB 00 91 57 BF 10 4A FF DF 52 A0 DF 7E 08 40 3E Û.‘W¿.JÿßR ß~.@>
00001F00 FF 00 00 B7 FF 00 02 FF DF 84 08 FB F7 30 14 FF ÿ..·ÿ..ÿß„.û÷0.ÿ
00001F10 FF 0A 10 7B FC 0A 00 DF C7 A1 C2 FF EF 20 00 FF ÿ..{ü..ßÇ¡Âÿï .ÿ
00001F20 FD 62 00 7F 7F 44 20 AF F7 80 80 B5 FF 41 20 DD ýb...D ¯÷€€µÿA Ý
00001F30 FF 30 00 FF E7 03 10 FB B7 00 10 DF F5 40 61 FF ÿ0.ÿç..û·..ßõ@aÿ
00001F40 FA 00 21 3F FF 40 50 BF 8F 05 B0 9F CF 00 00 DB ú.!?ÿ@P¿..°ŸÏ..Û
00001F50 7E 0A B0 37 FE A0 08 7F 7F 90 38 ED FF 49 32 FB ~.°7þ ....8íÿI2û
00001F60 EF 00 20 EB 3F 03 10 FF 7D 00 31 6F FB 10 1A FF ï. ë?..ÿ}.1oû..ÿ
00001F70 F7 10 C1 D7 FF 50 11 FD FE 50 02 BD FE 22 00 EF ÷.Á×ÿP.ýþP.½þ".ï
00001F80 FF 40 08 DF EB 04 00 DF 3F 80 08 AD 9F 01 00 DE ÿ@.ßë..ß?€..Ÿ..Þ
00001F90 F7 10 89 7E FF E4 40 E3 FC 22 00 FF FF 00 80 5F ÷.‰~ÿä@ãü".ÿÿ.€_
00001FA0 E3 C2 00 EA DF 40 01 BF 7D 10 18 7D FF 00 80 FE ãÂ.êß@.¿}..}ÿ.€þ
00001FB0 EF 02 00 BF DF 00 0A FF F7 08 D0 FF FE 80 00 5F ï..¿ß..ÿ÷.Ðÿþ€._
00001FC0 FB 01 50 5D F7 10 01 7F 3F 00 14 EF D7 00 08 6F û.P]÷...?..ï×..o
00001FD0 F7 50 02 BD FE 80 08 FF F6 60 14 ED AF A4 06 EF ÷P.½þ€.ÿö`.í¯¤.ï
00001FE0 7F 02 00 E7 FF 82 08 FF FE 04 21 3F FD 00 44 F7 ...çÿ‚.ÿþ.!?ý.D÷
00001FF0 FF 20 00 7D FF 10 20 FD BE 24 10 F4 BF A0 0A FB ÿ .}ÿ. ý¾$.ô¿ .û
--- End code ---
These are the calibration constants for the scope, I verified it by doing calibration ram exerciser 02 :
https://youtu.be/-Upu0b4jBlA
As you can see it matches, from the service manual I know that the data is 14 bits (including parity), that's a maximum 3FFF in hex !
As you can see lots of it is way higher that that :-// also parity is all over the place.
I'm at loss how it got scrambled so badly?
Attached a ful 8K image of the memory, maybe someone will be able to figure it out?
MarkL:
It looks like you have a diode to power up the SRAM. Did you read the SRAM while the scope was powered off?
If so, that's interesting that it worked given that the programmer was driving all those off components through their I/O pins.
What are the resistors doing?
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