Tek 7603 readout repair - Page 1
Forum section: electronics / testgear

author: Martin.M
author_rank: Frequent Contributor
timestamp: May 14, 2017, 07:23:20 am
content: hello friends,I am more familiar with tube oldies, this 7603 is a new thing on my table.There is no readout comming, I need to know how to make the measuring in the readout board to catch the bad IC there.!! I am pretty shure to have the readout ICs all in stock, but I don`t want to destroy a new one, so I need the test.Here are enough scopes present to do thatgreetingsMartin

author: capt bullshot
author_rank: Super Contributor
timestamp: May 14, 2017, 08:50:09 am
content: First, I'd check if the readout is turned on at all. Maybe by watching the horizontal deflection signal in auto trigger mode, free running at a medium timebase setting. If the readout is active, the ramp signal gets interrupted by the readout, this is clearly visible.Then check the inputs and outputs of U2126 (Timer) - this is the one controlling the whole readout system. Of course, check the power supply voltages of the readout board. Check the readout intensity input, if it varies with the setting of the readout intensity knob. Check the setting of the readout mode switch (S2110) on the board, set it to "free run".At the moment, and with the information you give, I'd suspect the readout doesn't get turned on or failure of the master controller chip (that would be the "Timer"), maybe the S2110 in triggered mode (the readout won't display if the scope isn't triggered)

author: dave_k
author_rank: Frequent Contributor
timestamp: May 14, 2017, 10:16:55 am
content: What version of the readout board do you have? There were a couple of different versions produced during the production lifetime of the 7603...

author: Martin.M
author_rank: Frequent Contributor
timestamp: May 14, 2017, 01:00:11 pm
content: ouchI have opened that 7603 now and think now there is no readout board installed.But the scope have at front the pot readout intensity, and there is no "N" or Option 1 to find outside.Or I am to stupid to find the board, that may be possibleI have a readout borad in my spares collection, 670-1900-06but no cables to install that in the 7603Martin

author: capt bullshot
author_rank: Super Contributor
timestamp: May 14, 2017, 02:14:51 pm
content: Maybe you're able to build your own cables, the Tektronix Peltola connectors are simplehttp://w140.com/tekwiki/wiki/Peltola_connectorbut if you don't have some, I don't know where to get them. I'd try to stick some coaxial cable with rigid inner conductor into the sockets without the gold piece. The others can be made of single row precision contacts like these:https://www.reichelt.de/Buchsenleisten/BL-1X10G7-2-54/3/index.html?ACTION=3&LA=2&ARTICLE=180551&GROUPID=7435&artnr=BL+1X10G7+2%2C54&SEARCH=%252ADo you know this one:http://www.amplifier.cd/Test_Equipment/Tektronix/Tektronix_7000_series_mainframe/rep-und-kal-7603/Reparaturbericht%20TEKTRONIX%207603.htmThere are pictures of the location of the readout board

author: guido
author_rank: Regular Contributor
timestamp: May 14, 2017, 03:33:32 pm
content: I might have the cabling availble. Have a 7603R parts unit. So i would have to check if the cables have the correct length...