Vintage Tek 230 Digital Unit wants to screw me up - Page 1
Forum section: electronics / repair

author: benedienst
author_rank: Newbie
timestamp: August 12, 2015, 04:24:09 pm
content: Hello together,I'm a new one, so I want to introduce myself a littlebit:My name is Ben from Germany with a heart for vintage Testequipment. Starting with my first scope, a tek 547 in really bad shape, I now own a really well equipped lab of vintage T&M (Tek most of it, someone will guess I'm a fan...hmm). OK so far, now to my Problem:It's a few month ago, I got Hands on a rare Tek 568/230 progtammable sampling and automated measurement System. A few words to it. The 568 is mostly like the 561 only with extra connectors for readout and programming. It's normal usage is with the Tek 3S5 and 3T5 programmable sampling plug in Units. With a S4 Sampling Head, it is able to capture risetimes up to 25ps (I only own a S3 with 300ps active sampling probe). You can use it for stand alone, but it is primarily designed to work with a type 230 Digital Unit as an automated measurement System for Amplitude, Time and it's correlation. My issue now is with the 230. A nightmare of discrete, RTL and ECL logic.A description and the full Manual with schematics, circuit description, etc. you can find here :http://proxy.w140.com/tekwiki/wiki/230you'll Need the late Manual.Problem is, that I have the measurement Start and Stop Zones, but I have no Measuement Zone intensification and no readout update on the Nixies. Main start Signal for the measurement cycle is generated on the P9 SYNCHRONIZER board with the Delay Generator, which is controlled with the "VIEW TIME" Knob on the FP. the MEASURE condition is obtained when MEMORIES /CHARGED is LO and the Pulse forming circuit around M1760 is giving a Pulse to M1720 which is the MEASURE FF.I found out that the Amplitude of the pulse which should latch up this FF is possibly not high enought to do that. The Signal is only near to a Volt, so around 0.8 to 0.9 V (where most other amplitudes are such around 1,6V up to 4V). Becaue I'm not familiar with this type of logic, i can't expect the reason why I have a switching function but as it seems, with to low Amplitude.I hope someone is out there who is still familiar with RTL and old ECL and can help me with my Problem.regardsBen

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: August 13, 2015, 12:06:35 am
content: Ah, we are brothers. I have a 547, and also a 567 with 6R1A Digital Unit, the ancestor of the 568. However it got bent in shipping so I put it away.It's quite a monster. You should go over to the Yahoo Tekscopes group, that's where all the Tek folks hang out.https://groups.yahoo.com/neo/groups/TekScopes/conversations/messagesI'd check all the supplies first, and maybe remove and reinstall all socketed parts, including the cards themselves. Eliminate the mechanical stuff first.

author: singapol
author_rank: Frequent Contributor
timestamp: August 13, 2015, 03:26:49 am
content: Quote from: Alex Eisenhut on August 13, 2015, 12:06:35 amGood advice, I second it especially something made in the sixties...very old and contacts could be corroded/oxidised and power supply has aged.Take note there is +/- 50V and a unregulatedd 255V for the nixies or scope intensity adjust among other logic voltages? The main power filter caps could have detoriated.Good luck.

author: benedienst
author_rank: Newbie
timestamp: August 13, 2015, 04:32:57 pm
content: The yahoo Group is a good idea. Because I'm very helpless with this Problem.Cleaning, checking Powersupplies, sockets and visible defective components is always the first thing I do, when restoring a vintage Piece of Equipment. It's not the first time I do that.So, I will go on and try out the guys at yahoo.regards Ben