James's Vintage Workshop Stuff!

jamesinc

I started this thread to document some of the stupid things I have bought in the pursuit of basically being able to do everything in my home garage. Rebuild, calibrate, tune, modify, diagnose, fix, verify. What can I say, I have an engineer brain and I don't like sitting still, and I am dangerous enough with a soldering iron that I can fix most oldschool discrete-component electronic systems.

Behold, my latest acquisition!

You had BEST BELIEVE I spent some time going over this with the multimeter before connecting anything. The plugs were all in pretty poor shape so I lopped the ends off and put new ones on. I tested for earth and live leaks, the main oscilloscope had the live and neutral wired backwards.

The stand includes a swing arm that holds all the leads and conveniently just clears my garage door.

PRESENTING THE BOSCH MOT-201 COMPACT ENGINE TESTER (top shelf)

Along with a Bosch CO% exhaust gas analyser (bottom left) and parts-per-million hydrocarbon counter (bottom right).

The seller also gave me a bunch of unused filters, and an extra sensor pigtail so I can hook the scope up to things like hall effect sensors and so on.

The scope works although it does have a bit of drift, my other oscilloscope has a test signal function so I will hook it up to that and see if I can't get it calibrated. I suspect it's just drifting because it doesn't have a stable signal to read.

The original owner told me this cost a total of $16,000 when it was new (I paid $250).

Major Ledfoot

Home smog testing. Cool!

Ex850R

Nice! Very nice!

Is it a quality plastic or metal fascia?

jamesinc

Pretty much all metal.

I hooked it up to the car tonight and tested all the functions out, most of it is working, the only issues I've found are with the timing light (this may be operator error, I need to put plain English labels on all the buttons as the symbols don't mean anything to me) and the oscilloscope.

The scope's problems appear to be due (at least in part) to a failing transformer. When I bought the unit I considered there was a high chance that the transformer would need to be rebuilt. I opened the unit up and sure enough there is some scorching visible. I'll have to remove it and send it off to be rebuilt, it's much too complex for me, it has something like 13 output voltages.

paul0075

jamesinc
Pretty much all metal.
I hooked it up to the car tonight and tested all the functions out, most of it is working, the only issues I've found are with the timing light (this may be operator error, I need to put plain English labels on all the buttons as the symbols don't mean anything to me) and the oscilloscope.
The scope's problems appear to be due (at least in part) to a failing transformer. When I bought the unit I considered there was a high chance that the transformer would need to be rebuilt. I opened the unit up and sure enough there is some scorching visible. I'll have to remove it and send it off to be rebuilt, it's much too complex for me, it has something like 13 output voltages.

A mate of mine might be able to help with the transformer

jamesinc

Who doesn't love gawking at electronic guts? You can see the burn marks on the transformer also.

Unit QC May 22, 1987

PaddlerEd

That's cool - my FSM for the 80 series Land Cruiser still gives you all the numbers you'd need to look for if you hooked it up to one of those as part of the diagnostics fixes!!

jamesinc

@PaddlerEd JD's while-u-wait engine healthcheck coming soon ?

PaddlerEd

Mmmm JD

Just what I need to find today.... Not got any, but got some (proper) whisky in the house that'll do the trick...

jamesinc

I'm putting away a Spanish rioja tonight, $10 but after airing for a few hours it has come good.

jamesinc

@paul0075 there's a guy near me who rebuilds them, I asked him for a quote, see what he says if it is sky high I hit you up.

Otherwise, tomorrow maybe, or when I next get a chance, I will make the high voltage side safe and replace basically every capacitor as the scope beam deflection looks wrong to me. I honestly haven't mucked around with a CRT since I was about 17 so I could be wrong but if memory serves, beam alignment/deflection issues are usually capacitor related.

Philia_Bear

@jamesinc you should also test all of the high voltage electrolytic capacitors, very likely one of them may be bad as well putting extra load onto the transformer

Also... what's the output voltage of the transformer? may be easy enough to find new if its a sorta standard voltage

jamesinc

@Philia_Bear yeah that is definitely on the cards. On the HV side I will probably just replace all the caps either way. Good insurance.

In terms of the transformer, it's a bigboi, as best I can see it has around 13 different output voltages and maybe more than one secondary winding. Bunch of 10-20V outputs and some 100-200V outputs.

timbo

I have an mot-201 that you're welcome to have for spares. Haven't tested it though

jamesinc

Man I will definitely say yes to that, parts and spares are non-existent for this thing.

jamesinc

I had a quick look again this afternoon so I could work out what caps to order.

The internal layout of the unit is very nice, as you might expect from the Germans. I thought this unit was from '87 however I think that may just be a service sticker, I found a printed label with 5/81 on it so potentially this unit is actually from 1981!

I've got the power distribution board figured out and it appears there are just three separate DC power circuits, each with its own full bridge rectifier.

To continue I need to find my solder sucker so I can start pulling caps and testing and replacing them. I intend to replace pretty much every electrolytic cap on the board, there's 20 or so in total not too bad at all.

Major Ledfoot

From the good old days, when it was possible to replace components to repair equipment.

jamesinc

And if you want to know what it all does...

Ex850R

YOU ROCK!

timbo

Did you get any manuals with your setup?