Freeze spray?

[MeanUncleBob]

Someone in another forum suggested using this to check for bad capacitors. He said that dying or bad ones produced much more heat or were hotter than good ones. When I looked it up I only found it for sale and no instructions on using it.

So, do you think it's a useful tool and if so can you tell me how it would be used?

Thanks

[PCBONEZ]

Re: Freeze spray?

>> So, do you think it's a useful tool <<

Nope

[bluto]

Re: Freeze spray?

It depends on the circuit involved and the symptoms. If the problem goes away after the device 'warms up' then freeze spray can be helpful. I have had two instances in devices that I fixed where this was the case. The first was a Toshiba tv where the whole picture was collapsed into a small horizontal line in the middle of the screen. As it warmed up, the picture gradually started expanding outward (headed towards normal). There was a bad cap in the vertical circuit. Hitting it with freeze spray while the tv was on made the picture instantly collapse back to the small line that was observed when the tv was cold. This told me which cap to replace. The tv still works fine to this day.

My other example is similar. I had a late 80's Kenwood amp that had static in one of the channels until it 'warmed up'. It turned out to be a single bad cap in the equalizer section (it had a circuit board for the slider things on the front with several caps on it). Freezing the bad cap caused the static to come back. I ended up replacing all the caps in the equalizer section while i was at it. But again in this case the freeze spray pinpointed the problem.

So yes it can be a useful tool depending on the situation.

[PCBONEZ]

Re: Freeze spray?

Except that the operation of good caps will change with temp too.
- So, you can easily 'duplicate' the problem by creating a new one that wasn't there in the first place.

The thermal shock can crack open cap vents or crack silicon wafers, solder, ceramics, plastics or glass.
You can also have condensation problems if the humidity is just wrong.

Odds of it showing you anything useful is very low and the risk is high, especially on modern PCBs.

[Wizard]

Re: Freeze spray?

In my experience, it is not really necessary to have this spray as long as *know* that electrolytics ESR rises with temp drop. Marginal capacitors of this particular shows up when cold, I always check with ESR meter and if they were not the problem then if the device still misbehaves when cold, I get heat gun and warm specific areas and get the problem to go away or appear vice vesa.
And that usually is IC or transistor going sick.

Cheers, Wizard

[cadiman]

Re: Freeze spray?

I used this to find solder issues in delco radios on the logic boards and dash clusters. I used a refridgerator (40 degrees) or freezer (0) to get hard to find problems to show up and only to find solder cracks. their radios would work on a warm day or not work in the morning. Same problem with Toro equipment using computer controlled hydraulics. Most of the problems I deal with involve hot, cold, and vibration. Everyone has their own way of finding the problem.

[PCBONEZ]

Re: Freeze spray?

Do you know where to find Delco part numbers?
I have several pounds of mixed NOS Delco IC's from an old radio shop that closed but no way to ID the chips.

[Krankshaft]

Re: Freeze spray?

Freeze spray is simply R-134A refrigerant in a spray can you can buy it from almost any auto parts store albeit without the fancy push nozzle. Just make sure it doesn't have refrigerant oil or stop leak included.

Nozzle up you discharge gas refrigerant nozzle down you discharge liquid refrigerant.

One time I used it in a TV with an intermittent vertical problem turns out it was as the temp on a zener regulator that through a transistor supplied the VCC of the vertical IC when it was low so was the VCC to the IC so the vertical height didn't fill out the screen.

As the zener heated up both from its own generated heat and the heat from the nearby regulator transistor the voltage slightly rose and the screen filled out to full vertical height.

The final fix as suggested my Plainbill I believe was to but a diode in series to up the cold voltage. This filled the screen up to about 1/8th total so to fix that I just nudged the vertical height in the service menu 2 numbers or so. So the screen was full when the TV was cold.

So in that one situation yes freeze spray saved me. Only though because I was certain the problem wasn't bad caps and had to do with the temperature of certain semis.

I honestly can't think of any other times the stuff has been useful though.

[bluto]

Re: Freeze spray?

Whenever I have had a need for freeze spray, I used a canned air duster held upside down. I read somewhere that the only difference between that and actual freeze spray was the location of the dip tube inside the can. So when a can of air duster is held upside down, the liquid comes out instead of the gas. And the liquid is very cold! According to Wikipedia, such air dusters do contain refrigerants including R-134a. I guess I always assumed that what was used in air dusters was more benign. Not so!

[Krankshaft]

Re: Freeze spray?

They need to use refrigerant because they need a condensable gas for an air duster something that can remain in it's liquid state until it's needed then it can vaporize into a gas and exit the nozzle. That way you can get a sufficient quantity in the can.

There would be very little air in there if they just filled the cans with a gas.

[Old Poni]

Re: Freeze spray?

Hi Pcbonez
Did you get any additional information about Delco?
I'm also trying to point out smth about it but with poor result.
Could you please to give me list of Delco chips you have.
It could be interesting for both of us.
I'm Yuri.
ponitech@yandex.ru
old_poni_skype
Best regards

[PCBONEZ]

Re: Freeze spray?

Hi Pcbonez
Did you get any additional information about Delco?
I'm also trying to point out smth about it but with poor result.
Could you please to give me list of Delco chips you have.
It could be interesting for both of us.
I'm Yuri.
ponitech@yandex.ru
old_poni_skype
Best regards

Ah, I could give you a list in a few days probably [it's packed away now] but I'm not shipping to RU short of a prepaid cashiers check that clears the bank.
[As in not using Paypal to anywhere I can't track it.]
.
Only time I ever looked into shipping anything to RU the shipping charge was stupid-HUGE. I forgot what it was exactly but the charge was like over $100 for something no bigger than a CD drive..
.

[Old Poni]

Re: Freeze spray?

Yes. So it is. Our customs searching our pockets as real hoodlum! But let's start with parts list. Of coarse we are talking about brand new chips but not being used?!
Also mark your price for each piece, please. Payment and delivery should be our next terms.

[Old Poni]

Re: Freeze spray?

Good morning, PCBONEZ
No news for me yet about Delco? I'm waiting list of parts:-)