Author Topic: tek 2215 (Read 6015 times)

m3vuv · « **on:** October 20, 2021, 03:33:07 pm »

Hi all,i have a tek 2215 just delivered from ebay in a crusty condition,i want to get inside of it to clean it,trouble is the service manual says remove the 2 screws holding the rear cover,then slide the cover off,i have done this but it seems solid!,am i missing something here,i dont want to break anything,tia paul m3vuv.

m3vuv · « **Reply #1 on:** October 20, 2021, 03:53:06 pm »

dont worry about this,i have the covers off,there was a srew in one side i haddnt spotted,while im in there are there any caps that i should change,ie riffa etc?.

bob91343 · « **Reply #2 on:** October 20, 2021, 05:23:56 pm »

If it's not brokem, I wouldn't fix it.

David Hess · « **Reply #3 on:** October 21, 2021, 12:36:09 am »

Before you continue, double check whether it is a 2215 or 2215A; they are very different instruments, and the service manuals are not interchangeable.

m3vuv · « **Reply #4 on:** October 21, 2021, 02:40:13 am »

it isnt the a version,im more concerned with doing some preventitive maintenance while i have it apart realy.

m3vuv · « **Reply #5 on:** October 21, 2021, 03:10:14 am »

just noticed both channel 1 and 2 are way to low down the screen,as in when fed a sine wave etc the lower portion of the trace is off screen,the position knobs dont seen to do a lot,any ideas where to look,it does it on both channels.

David Hess · « **Reply #6 on:** October 21, 2021, 03:48:42 am »

Quote from: m3vuv on October 21, 2021, 03:10:14 am

just noticed both channel 1 and 2 are way to low down the screen,as in when fed a sine wave etc the lower portion of the trace is off screen,the position knobs dont seen to do a lot,any ideas where to look,it does it on both channels.

Is the amplitude correct?

The output load resistors on the vertical CRT amplifier are known to overheat and go open on the 2213/2215 which might cause that.

m3vuv · « **Reply #7 on:** October 21, 2021, 04:05:02 am »

its hard to tell on the amplitude as i cant see the bottom of the trace,any idea where the resistors are located ?.

m3vuv · « **Reply #8 on:** October 21, 2021, 04:23:20 am »

if the load resistors are r378,r379,r389 and r 388 they measure as follows r378=314 ohm,r379=309 ohm,r389=321 ohm and r388=316 ohm.

m3vuv · « **Reply #9 on:** October 21, 2021, 04:23:52 am »

none show signs of getting hot.

andy3055 · « **Reply #10 on:** October 21, 2021, 05:35:34 am »

I have a 2215 and will follow this thread.

m3vuv · « **Reply #11 on:** October 21, 2021, 05:48:44 am »

hi andy,im pretty sure its q386 and q 387 in the vert amp that are shot,im trying to find out if i can sub bfy 50 or bc108 transistors in there place as i have these to hand

m3vuv · « **Reply #12 on:** October 21, 2021, 06:07:40 am »

testing q 376 in circuit,as in diode voltage drop,+ve probe on the base i get base to emitter 0.1v and base to collector 0.7v drops,the base to emitter junction looks iffy to me.

m3vuv · « **Reply #13 on:** October 21, 2021, 03:32:31 pm »

does the transistor readings make it leaky or low gain,ie,should i replace it?,tia m3vuv.

andy3055 · « **Reply #14 on:** October 21, 2021, 04:22:15 pm »

Q386 and 387 are listed as BFR96 and S006075 respectively. I could not find any data so far on these. I would check the voltages as per the service manual first. Also, if anything is amiss, check them out of the circuit.

Noticed your last post says Q376. Is that a mistake?

m3vuv · « **Reply #15 on:** October 21, 2021, 04:28:51 pm »

sorry meant to say q386,anyway i changed it for a bfy50,made no difference,also the two resistors feeding the deflection plates should be 51 ohm,mine both read 57,would that make much difference?

andy3055 · « **Reply #16 on:** October 21, 2021, 06:51:56 pm »

I am not sure. although I don't think it matters, you can eliminate by putting in new parts there. I have not gone into details very much on this scope as mine is working with no issue. If I get some time to read the manual, I will make some comments here.

andy3055 · « **Reply #17 on:** October 21, 2021, 07:09:59 pm »

CH1/CH2 position controls are associated with Q177/187 and 277/287, respectively. Since both traces are off to one side, I would start tracing backwards from those. I think it could be a voltage related to those and/or the transistors before them.

I am looking at "CH1 &CH2 Vertical Preamps" - foldout 2.

David Hess · « **Reply #18 on:** October 22, 2021, 01:07:15 am »

Quote from: m3vuv on October 21, 2021, 04:23:52 am

none show signs of getting hot.

That is odd. They should show signs of running hot and the printed circuit board should be discolored under them.

m3vuv · « **Reply #19 on:** October 22, 2021, 03:17:53 am »

well,i removed q387,it tests ok bith a beta of 84.

m3vuv · « **Reply #20 on:** October 22, 2021, 03:19:56 am »

what page of the manual are q 177 ect on?,i cant find it.

andy3055 · « **Reply #21 on:** October 22, 2021, 04:13:37 am »

Foldout 2. Check and Check vertical preamps. You also got some good feedback on Tek groups.

m3vuv · « **Reply #22 on:** October 22, 2021, 05:38:39 am »

i only have the service manual on pdf,ive just replaced the 4 riffa caps in the psu,used blue x types,only 2.1 nf not 2.2 like the originals but rated at 8kv.

andy3055 · « **Reply #23 on:** October 22, 2021, 06:14:34 am »

Open the pdf. Do a ctrl+f and that will open a little field for search. Type in Q177 and see if it will find it. I can check the pdf and get back to you in a bit.

m3vuv · « **Reply #24 on:** October 22, 2021, 06:22:14 am »

the search cant find it.


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Author Topic: tek 2215 (Read 6015 times)

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