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On Wed, 19 Dec 2012 17:00:50 -0500, Bert Haskins
<bhaskins@...> wrote:

>On 12/19/2012 02:34 PM, David wrote:
>>
>> Just to be clear, the STORE/NON-STORE button in the top row all the
>> way to the right does not do anything either?
>>
>It slightly changes the horizontal calibration.

You mean it shifts the horizontal position a bit? That makes sense
because 1 pole of the STORE/NON-STORE switch changes the horizontal
position on the analog side to set it up for the digital display. That
is independent of anything the digital side of the oscilloscope does.
The other pole enables DSO mode in the kernel.

>> Make sure to check the position of the STORAGE/READOUT INTENSITY
>> control just to the right of the CRT.
>>
>> Since the readout is completely missing in analog mode but the analog
>> oscilloscope apparently operates, if the above checks out, then I
>> would suspect the digital board is malfunctioning. You are probably
>> going to need a service manual to proceed.
>>
>This is like the "readout toggle on off" except that it is just off..
>doesn't toggle.

And the storage display never shows a trace because it never
activates, right?

The readout toggle function on the 2230 only applies to the readout
and not to the digital storage trace so it is possible to disable the
readout but still have a digital storage trace visible with one
control.

>So I guess I'll have to check that out in the manual.

The service manual has a whole procedure for checking just the kernel
(page 6-8) which includes the microprocessor, clock, and address latch
but you probably need another working oscilloscope to do it and it is
only going to reveal if the kernel is working or should be working. I
*think* it should be possible to diagnose it using the 2230 working in
analog mode two traces at a time.

On the other hand, checking the kernel is probably a very good place
to start, after the power supply voltages, because a malfunction there
could easily cause the problems you are seeing.

The problem could be as simple as an IC

Close!

or connector popping out of
its socket because of thermal cycling.

Sorry about the late reply:
While searching for the answer to this, I happened to touch the probe
to one of the pins on one of the eproms ( CE I think ).
When the probe made contact, the 7-segment readout changed from
a "8"? to blank and the readout appeared.
Removing, cleaning the eprom and socket fixed the problem.
This was not one of the crappy TI sockets it is a Berg/Auget style dual side wipe.
First time I've seen a problem in one of those.

Removing, cleaning the eprom and socket fixed the problem.

This was not one of the crappy TI sockets it is a Berg/Auget style dual side wipe.

First time I've seen a problem in one of those.

One of my standard troubleshooting techniques is to use a small screwdriver to lift all socketed ICs (not so much as to remove a pin, just to wipe the contact) and reseat them. Just a small twist of the 'driver at each end then reseat.

Dave

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> Removing, cleaning the eprom and socket fixed the problem.

> This was not one of the crappy TI sockets it is a Berg/Auget style dual side wipe.

> First time I've seen a problem in one of those.

One of my standard troubleshooting techniques is to use a small screwdriver to lift all socketed ICs (not so much as to remove a pin, just to wipe the contact) and reseat them. Just a small twist of the 'driver at each end then reseat.

Dave

I agree, and had done that but in this case only removing and cleaning worked.
I guess that I just got lucky in that the probe tip made the missing connection long
enough to "shout out" the real problem.

On Mon, 21 Jan 2013 10:39:51 -0500, Bert Haskins
<bhaskins@...> wrote:

On 12/19/2012 05:39 PM, David wrote:

. . .

The problem could be as simple as an IC

Close!

or connector popping out of
its socket because of thermal cycling.

Sorry about the late reply:
While searching for the answer to this, I happened to touch the probe
to one of the pins on one of the eproms ( CE I think ).
When the probe made contact, the 7-segment readout changed from
a "8" to blank and the readout appeared.
Removing, cleaning the eprom and socket fixed the problem.
This was not one of the crappy TI sockets it is a Berg/Auget style dual
side wipe.
First time I've seen a problem in one of those.

It might be worth reflowing the solder connections on that socket.
Maybe there was a cold or failed solder joint. Take the IC out if you
do that though so the tinning on the leads does not solder it into the
socket.