Products > Test Equipment
Sony-Tektronix 308 Data Analyzer
jrharley:
Hey thanks TurboTom! Really appreciate you trackin' this.
All good thoughts. I'll give the button push a try. So far, keys have been unresponsive, but I haven't been specific in my approach.
With reference to "original display pattern", I feel like it's important to keep in mind that the original display pattern was a recognized error code - 03-04. So I'm thinking the "kernel" was operating properly at the point of initial power up. After messin' with the RAM chips, I haven't seen that original screen again.
I think I'll go push some buttons.....
Later
JRH
TurboTom:
Signature analysis instructions start from page 192 of the manual PDF. FYI, I attached the page starting with signature analysis of the ROM system. Topic A specifies where the control lines are to be attached to and what polarity should be selected. B gives you informations on the configuration of the DUT. C is a cross-check to make sure the signature analyzer is configured correctly. In table D, finally, the test points are specified together with the signature that should be read there.
This continues over several pages so it's possible to signature test the whole digital circuitry of the Tek/Sony 308. There's little that's not covered in the manual, but it's a huge amount of information and sometimes it's difficult to find exactly what you're looking for.
jrharley:
I'm freakin' out here Turbotom! :-//
I just went in to the shop to power the unit on and confirm that the buttons you referenced didn't respond. Upon power up, the guy showed the original error screen again !! I guess you just never know what's next. I powered it up, expecting to see the scrambled screen I have been seeing, but the damn thing booted up with the original error screen again.
The only change since the last power up was re-installing the jumper, P410, back into circuit. Oddly, the jumper is composed of individual, across 2 pin blocks. One Dupont style connector block jumps across 2 pins. There are about 8 of these jumper blocks that make up P410. Connection issues seem to be complicating the analysis here. The "triggered" LED indicator on the keyboard also lit up, which didn't happen earlier.
This certainly changes the troubleshooting tree path. I'll post up when I learn more.
Sheesh!.........
JRH
Tony_G:
Nice - Might be the ol' dirty contact issue.
Look forward to the next update.
TonyG
jrharley:
I am so jazzed right now I could stay up all night!
Thanks for the comments guys!
First step tonight was to clean all the terminals on the P410 jumper assembly.
TurboTom, your original statement has proven to be spot on. :clap: I realized you were right about that when I re-visited the tree, based on the recent developments. It led me straight to a box that just said - "replace the RAM device". And so I did once again. This time, I was a little more selective in replacing one of the original chips. U420 always looked a little "off" to me. It didn't have the same markings as it's sista' chip, U422, which matched several other chips in the circuit serving different functions. So I put a new RAM chip in there first.
Sweet, ever lovin' analyzer, if the thing didn't boot up with what appears to be the correct screen!
I've got to go through the start up checks of course, but this guy appears to be working! Tonight, I will dream of electric sheep........ ;)
I'll post up shortly with pics and info as I get my mind around this amazing and unexpected development.
Later,
JRH
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