Hickok 288X Signal Generator Restoration

For the first time in a while, I'm going to work on something radio-related.

This is my Hickok 288X signal generator - it dates to about 1950.  If you're not familiar with signal generators, what this does is output AM, FM, or audio frequencies to use when aligning and troubleshooting radios.  I have an old Hallicrafters signal generator I've used for alignments in the past, but I have a handful of FM sets now and a sweep generator is needed to align them.  A few years ago I snagged this to do FM alignments.  I haven't even plugged it in.

I'm going to see if it woiks, and then go through it and recap it (change out all the old capacitors which go electronically leaky over time).  Then I'm going to align my RF-2200.

I love old test gear, especially something like this with lots of controls.

I've seen a lot of these old generators on the web - and virtually all of them are missing the plastic cover that went over the frequency dial.  Maybe it was the way they were mounted, but I don't think I've seen on with the window/cover on.

I have some thin plastic I've been saving for this project - I'll just fabricate a new one.


Taking the chassis out is easy - nine sheet metal screws hold the front panel to the cabinet.  The chassis is attached to the front panel, so it all comes out as one assembly.

This was designed to be easy to service. 

Hickok's stuff was 'service grade' - aimed at radio repairmen.  As such, it was pretty well made and rugged.  Not as high-end as say, Hewlett-Packard or Tektronix, but not consumer-grade like Heathkit.


I pull the chassis out and get a great surprise.  The missing dial cover is inside the cabinet!  Wow.  How great is that?

The chassis on the bench.

There are two sheet metal covers over the inner works.  This was done as an RF shield.  There are also two access panels on each of the two boxy covers - taking them off allows access to components that would need periodic adjustment.

Well thought out, and again, made to be serviced.

Here's the chassis tipped on its side and viewed from the bottom.  All of the tubes, except one, are here.















Bottom cover removed.  I'll be changing all the paper capacitors in the bank of caps on the left.  There's another one to the right, and one up under the meter (near the top).

The filter caps are in a can - I think I'm going to disconnect that and just put new caps on the chassis.  A lot of times I'll restuff the cans, but there's plenty of room to just fit new caps on the chassis.

There's also one more capacitor inside the second, 'tuner' box.

Point-to-point wiring like this is a lost art.  Look at how one lead was threaded through a terminal strip to help restrain it.

And also see the laced wiring loom on the left side.  This type of wiring originated with the telephone industry and carried over into quality electronics.  I have a book that outlines how to do this type of wiring.

The people who built this cared about what they were doing.  Very tidy indeed.

A little history.  Hickok was located in Cleveland, Ohio.  They were started in the 1930s and built radio (and later TV) test gear - tube (later transistor) testers, voltmeters, signal generators, etc.  The manual I have for this generator gives their address as:

Hickok Electronic Instrument Company
10514 Dupont Avenue
Cleveland 8, Ohio

I was curious to see if the building still existed, so I went to the interwebs.


Indeed it does!  This is the Google street view.  The building is on a corner of two streets - about 5 blocks from Lake Erie in Cleveland.  If you click on the image, you can clearly see the street number on the building (I left the image large for clarity).

And, the company is still in business as Hickok, Inc.. In looking at the pictures, the building is not as large as I would have expected.  Maybe they had a larger facility and downsized?   At any rate, it's interesting to see where my 288X was built!