FG504 end of production

John Ferguson

Hi guys,

I'm trying to acquire an FG504 for what to me would be a reasonable cost - might seem unrealistically cheap to you.

there are a few on Ebay right now including some which the seller says he's obtained from a Tek training facility.

I asked how long they might have been in storage and was sent the message blelow.  He mentioned checking dates on calibration labels - unit in photo,has seals but I don't know what Tek's own seals would look like.  What do you think?

I am very certain these were used in the last 20 years! These were
taking from active Tektronix production lines which were
decommissioned in the last 4 years. I don't have these ones in
front of me, so can't check for last cal dates. Most had cal dates
on them when I got them. I have sold two so far without any


I think I see the FG504s you are talking about.

It does look to be in good condition, but I would expect some issues for this age equipment.
The seller uses the typical dealer statement "Pulled from working environment".
Append "after it stopped working" on the end of that and you probably have a more accurate statement.

It is listed as used and working - so if you buy it and that statement is not true you can ask the seller for a partial refund or file a claim and get a full refund through ebay.


John Ferguson

Thanks Victor,

I've corresponded with the seller who does seem to have some technical understanding, but.....

I cannot believe that Tektronix was using fg504's for instruction in their own operations within the last 20 years. Does anyone know if this is likely?

I've already bought 2 of these things because I really do want one.  first was sold by son of departed tech hobbiest.  Someone had disassembled it and then put it back together without reconnecting the internal cables - bought as is so no complaint and i think the seller had no idea.

Second one was complete, looked nice and worked partially. Friend took a shot at reviving it and got most of the way done, everything works but upper frequency range is a bit out of cal and some of the trimmers involved in calibrating are really stuck, need to be replaced which would stretch our friendship a bit far.

In addition to the ones you've recognized, there's a TM515 with some other modules which I already have and an FG504.  Seller says everything is working and I think on the side of superstition, I'm more inclined to think this system has been in recent use and is more likely to work.  but then the price is higher but included things I don't need.



I see one of the ones that you are talking about ("pulled from Training Department") and it does appear to be in excellent condition; it may, indeed, have seen little use, based on the condition of the card edge fingers and the BNC connectors. Given the location of the seller I think it's certainly possible that it came from a Tek site. I wonder what kind of training it would have been used in where it would have gotten so little evident use. I also wonder how long ago it was pulled from that environment.

It's being offered as "used" which should give you some protection (or recourse) if it is not working. I don't think that the price is unbelievably low. Have you gotten pictures of exactly the item you would be purchasing ? Given that it says there were five available, and only a single serial number is shown in the pictures, I would worry that the others were not in similar condition.

If I were in the market for another function generator, I'd probably buy it, but I have a weakness for TM500 stuff.

-- Jeff Dutky

Greg Muir

Cal dates can reflect any time and be from anyone. The header in your message states “FG504 end of production.” That alludes to your wanting to find when the last FG504 left the production line to see how old these units are. But referring to a cal date is basically worthless. It will tell you when the unit (supposedly) met specs but that is not necessarily the case unless the name on the sticker reflects an accredited test lab who did the calibration.

There are times when I see items that are “cal’d” apparently by the seller who either adds a sticker or states so with little information about who they are, equipment used for calibration or processes used. I sometimes get the feeling that they turned the unit on, put in a signal from a Radio Shack generator or measured the output on their Eico scope. If it looks close, it is “cal’d.”

As for operation, the “powered up - works” people are another issue. Yes, the unit seems to work but how many capacitors or other components are toasting inside waiting to go up in flames after it has been in operation for more than 5 minutes?

Filtering out the “apples and oranges” here I don’t really see anything that reflects the age of these plug-ins. What you really need to do is research the serial numbers on the units and find someone who may be familiar with the age vs. serial number. Either that or try to locate date codes on the components to give you an idea of the vintage of the item by comparing the date(s) found to when the item was last advertised in the manufacturers catalogs..

If I found the correct seller he shows a unit with serial B059954. But the unit has no cal stickers, only a “94” label on the tip. That is probably the last inventory date.

42 years ago I picked up a FG504 that sported serial B042…. It was part of a suite on government surplus. When testing I found that it had no output. The problem was traced to a Tek custom IC which was obtainable at the time. That’s not the case these days so be very careful to make sure that the unit you purchase either works or that the seller has a return policy (which he apparently does).

I’ve come to believe (or not believe) anything that is read on ePay is basically heresay. A “working environment” may be true if people are moving around and working but is the equipment you’re looking at actually working?



Hello John,

That FG504 contained in a TM515 is no longer available.

Its seller has sold it separately and has not yet updated the ad in Ebay.


Greg Muir

I forgot to add another item – on the units with the small concentric knob with its surface painted red you can usually get a good estimate of use that the unit has received by noting the amount of red paint that has been worn off around the edges. That is, unless the seller or user has replaced the knobs but those items are hard to come by these days.