Need obsolete semiconductor source for TL607

Why that part?

It's for a Wavetek 3000B service monitor. Most of the IC's are in sockets which makes troubleshooting rather easy. This particular FET switch is used for switching the front panel meter. There are about 8 of them in the unit. Some clues as to whether it needed replacement are the melted IC socket and the larger volume of smog that the chip generated. To the best of knowledge, there is no substitute or equivalent. I have temporarily thrown together a piggy back board with a 4066 FET switch and 4069 inverter that was sufficient for getting things running. However, I would prefer the real part.

That's a tough one!

Not really. I've practiced parts cannibalism and circuit redesign before in order to replace obsolete parts. I recently performed a radical substitution for the traditional blown flyback xformer in a Tek T922 scope. If you know how the circuit works (and have an accurate schematic), then such redesign and substitutions are easy enough.

However, I'm lazy and have a limited amount of time to redesign the circuitry. I bought the Wavetek 3000b on eBay for about 60% of what it was worth. Having worked with similar vintage service monitors (Cushman, SSI, CT Systtems, TFT, etc), I thought it would be fairly easy to repair. Identifying the smoking part was easy enough. Replacing the melted socket was not much of a challenge. However, I'm currently stuck at finding a replacement IC.

This is not the first time I've searched for old parts. What I've found are various online "parts finder" sites, that will offer to find obsolete semiconductors. The ritual is to fill in an online request for a quote, and they will allegedly contact me with price and availability. All of them list their inventory online and most show a TL607 in stock, somewhere. One claims to have 11,000 available. If I needed 11,000 parts, this vendor might be useful, but I only need a few parts. In general, *AFTER* I fill in the info for a quote, the web page announces that there's anywhere between a $100 and $400 minimum purchase. Incidentally, the $100 is a lie because this vendor wants another $100 for "shipping and handling".

So, what I need is an online vendor, that sells small quantities of obsolete semiconductors and IC's, that doesn't have a ridiculous minimum. I suspect that this is a chronic and common problem in the repair biz and was hoping that someone knew of a reliable source.

Datasheet for the part:

JUNE 1976 - REVISED OCTOBER 1986

Perhaps someone could suggest an alternative part...

I've surfed the Australian sellers like Jaycar because they often have small quantities.

Have you tried just Googleing on the part #? Sometimes that will show up some in some odd inventory somewhere. There are surplus houses that may have them as well as individuals who might be tickled pink to get rid of a dozen.

We know they're out there; it's just a question of getting the willing buyer and the willing seller together.

----------------------------------------------- Jim Adney snipped-for-privacy@vwtype3.org Madison, WI 53711 USA

-----------------------------------------------

Of course I have. That's one way I found a selection of uncooperative and overpriced obsolete semiconductor vendors. The other is from the repair FAQ. These vendors maintain their "inventory" online and Google finds them easily. The common theme and problem is the $100 to $400 minimum order.

Try searching Google for: obsolete semiconductors "minimum order" as in:

Well, that's what I've been asking. So far, I haven't found a willing surplus house and was hoping that someone with a similar problem had found a willing vendor or supplier. Assuming that repair shops still exist that actually do component level repairs, I would think that finding obsolete and ancient parts to be a common problem.

Yep. That's exactly my problem. I'm a cheap and willing buyer looking for an inexpensive and willing seller with inventory.

Have you tried these folks?

They list the device you're looking for as WIP with an 18 week lead time, if you can wait. We buy small quantities (10) of old DAC80 and AM2504 parts for support occasionally. These folks actually purchase the masks from the original vendors when they go EOL.

Well, that's a bit extreme. I didn't know anyone was doing such things. I this case, 18 weeks is a bit too long and I suspect making a single wafer to supply about 10 parts is going to be rather expensive. I'll keep pounding on the "obsolete semiconductor" vendors until I find one that cooperates. Thanks much for the info.

They sometimes have the last wafer or two that was made by the OEM before the finished part was discontinued. On the other hand, they don't deal in small quantities. It would be nice if they would forward your request to the last company to buy the parts to see if they would sell a few.

No shortage of deranged idiots in the world!

Well, the TL607 was discontinues in the late 1980's so I don't think anyone is going to have 15 year old inventory laying around. Probably a good idea for more current obsolet components.

For entertainment value, the best quote so far is $5/chip with a 35 piece minimum, plus shipping. Grand total is about $170. Kinda expensive to fix a $300 piece of test equipment. However, I may have to take it if I can't find another source.

Grumble, grumble...

If you do, make sure to list the extras for sale on a website somewhere, because there have to be other people who will need one or more for a repair. I have someone order a couple NEC MC-5800 Hybrid RF/IF amplifier modules from my website. I am probably the only one listing this part outside of the big brokers. If I had the money I would like to deal in the spot market and buy some of these hard to find chips to sell in smaller quantities.

I am now disabled and can't do a lot of repairs so i listed a small part of my parts collection on a website to help others find a few parts here and there.