Hard to find clock oscillators

[Joseph Davis]

Hi there,

I'm dealing with a 4 Mhz clock oscillator that needs to be replaced with something slightly faster, but finding such low speed clock oscillators in this day and age is difficult. Is anyone aware of any old, legacy equipment that would have a 4.3-4.5Mhz clock oscillator?

It's for older circle track cars whose ECUs can't be flashed, they have an external ROM provision but if the ECU cover is pulled and that part of the board is populated (they are unpopulated from the factory) or there's a non-OE daughterboard in place then the car is disqualified. Most car guys being unversed in electronics, meh, there's a way around this.

Do the old 4.77Mhz PCs use a crystal or clock oscillator? That's a little higher than I would like to go, but it's the only thing I can think of off the top of my head.

Thanks!

 

[Papabravo]

Do you mean something like this:

**broken link removed**

 

[Speakerguy]

4.096Mhz is a common value. Is that not fast enough? 4.3-4.5 seems hard to find.

Edited to add: Here is one at Mouser. 4.43MHz in a 14-pin DIP (full size) case. It is pricey though.

https://www.mouser.com/ProductDetai...=sGAEpiMZZMsBj6bBr9Q9aTcYHpdhOqnCIYyVTtUmgZg=

Edited to add again: nevermind, I see they have an order minimum of 50 and it's non-stock.

 

[Papabravo]

I've always had good luck with these guys. The market for through-hole components is rapidly drying up.

**broken link removed**

 

[mneary]

[edit] Sorry, I posted a solution but had second thoughts about deceiving inspectors in a competition. [/edit]

 

[ParkingLotLust]

Here are a bunch on eBay:

**broken link removed**
**broken link removed**
**broken link removed**
**broken link removed**
**broken link removed**

 

[Joseph Davis]

Edited to add again: nevermind, I see they have an order minimum of 50 and it's non-stock.

Yeah, that's been my biggest problem.

Here are a bunch on eBay:

**broken link removed**
**broken link removed**
**broken link removed**
**broken link removed**
**broken link removed**

None of those are clock oscillators, sir.

[edit] Sorry, I posted a solution but had second thoughts about deceiving inspectors in a competition. [/edit]

You don't know much about racing then, no offense. Circle track = cheaters, especially the guys fielding $200 20 year old stock-ish cars where the cost of the roll cage is more than everything else on the car put together. At the end of the rulebook is states "Have fun, and don't get caught!" for a reason, because you'll finish dead last if you roll out with a truly stock car regardless of your driving skill.

Circle track guy commonly regear transmissions, run oversized tires and rebadge the tire size, offset cam keys to pitch the powerband upwards, and on the later ones I have done some discreet ECU tunes.

The big V8 car classes that allow driveline and engine modifications, and therefore cost a significant chunk of money, are sticklers for the rulebook (to a certain extent)... but then those guys aren't looking for a $5 solution for a dinosaur car with no aftermarket support, they can pay for a minimum order of 50 components without blinking. IIRC they pay $15K or so for an engine meant to last one season.

For your conscience:

**broken link removed**
https://dodgeforum.com/forum/805222-post1.html







PS - Thanks for the lead, Papabravo. Looks like they have exactly what I am looking for, now it just comes down to price/min order nonsense.

 

[Papabravo]

If the actual frequency is not that important then choosing one that would be of interest to hobbyists so you can sell the ones you don't need on eBay might be handy.

To do this pick the largest number inside your range which is an integer multiple of the standard serial communications bit rates. One of the magic numbers is 9600 and the other magic number is 14,400. Reduce these numbers to prime factors, find the LCM, then use factors of 2, 3, 5, 7 to get a result that drops into your range. There may or may not be a solution to this little problem but it should keep you off the streets....er...track for a couple of hours. Ahhhh...cha cha cha!

 

[mneary]

OK, I give in. It's not a race, if it's an explicit game of cat and mouse with the inspectors. I have a soft spot in my heart for actual racing. Naive? Maybe.

Digikey sells programmable crystal crystal oscillator cans, quantity one, for $5 to $10. Just tell them the exact frequency you want in the order notes. They'll probably write the freq. in India Ink on the top .