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Kenwood CS-6040 6040 Oscilloscope: Variable vertical control fault and HIC module

Steve Rawllings

New Member
I have a Kenwood CS-6040 oscilloscope with a similar fault to that described by 'fezder' at:

As the previous thread has been closed, I've started this one.

In my 'scope, neither the variable 'HIC' attenuator module for Channel 1, nor the HIC module for Channel 2 responds to the variable gain control voltage derived from their respective front panel controls. Although the calibration of Channel 1 is unaffected, Channel 2 is only reading about one seventh of the true VOLTS/DIV.

For now, I'm assuming that the HIC module has failed in a convenient manner for Channel 1, but the corresponding HIC has failed in a 'lossy' manner in the Channel 2 vertical amplifier.

Before I remove the HICs from the PCB, I'd appreciate any comments from others who have experience of these HIC modules, especially regarding possible alternative modules, or suitable home made attenuators.

Regards to all
Steve
 

Steve Rawllings

New Member
Removing the two non-working HIC modules was quite easy. But I needed to make a tool for removing the 7-pin modules from the PCB. The pins of the module were quite tight in the PTHs, and a solder pump wasn't removing enough solder. I needed to make something that would heat all the pins at once.

I started with a 15 mm copper T piece from my plumbing spares, which I modified using a hacksaw and file so that it would fit on my large 700 degree Weller soldering iron bit. Removal of the two HIC modules was an easy task using this home made de-soldering tool!

I then replaced the PCB and was delighted that the correct vertical gain had been restored to Channel 2! And Channel 1, which would occasionally flicker, was now stable.

It's clear that the HIC attenuator modules really let down an otherwise superb 'scope. Removing them at the first sign of trouble is probably the best thing to do. Happily, most tasks do not require variable vertical gain.

Regards to all,
Steve
 

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Nigel Goodwin

Super Moderator
Most Helpful Member
Those types of modules (not just in scopes) have always been pretty unreliable, you used to get them failing in TV's and VCR's etc. - either technology moved on, or the manufacturers realised they were unreliable, as they faded out of use.

BTW, do you always use your scope upside down? :D
 

Inquisitive

Super Moderator
I think it's an Australian scope Nigel :cool:
 

Steve Rawllings

New Member
The tweaky pots for the vertical amplifier are on the underside. Adjustments were easy to make when following the procedure in the manual.

I’m waiting for a new clock battery to arrive and then I’ll be putting the covers on. A couple of weeks ago, only Ch 3 was working. Now it’s a four channel scope again. Happy days.

Thanks for the information, Nigel, about the HIC and similar custom modules. I’m glad that such custom modules weren’t used in more critical areas of this model of oscilloscope.
 

Nigel Goodwin

Super Moderator
Most Helpful Member
The tweaky pots for the vertical amplifier are on the underside. Adjustments were easy to make when following the procedure in the manual.

I’m waiting for a new clock battery to arrive and then I’ll be putting the covers on. A couple of weeks ago, only Ch 3 was working. Now it’s a four channel scope again. Happy days.

Thanks for the information, Nigel, about the HIC and similar custom modules. I’m glad that such custom modules weren’t used in more critical areas of this model of oscilloscope.
As an engineer I found them REALLY annoying, it's not like there's a great deal on them, yet they are such a specialised item that they rapidly become obsolete.
 

Steve Rawllings

New Member
I would like to record my grateful thanks to Fezder for his original post about the CS-6040 and the unreliable HIC modules.

Fezder’s investigative work, and his clearly recorded fault history, saved me a lot of time.
 

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