Philco 37-89 hot tubes

http://www.nostalgiaair.org/Resources/226/M0013226.htm

I have a Philco 37-89 in the process of rebuilding. I have checked the tubes and replaced a few caps and resistors but still have few (caps\resistors) on order. The rectifier (5Y4) and output (6F6) are both running
very hot to the touch. Anyone have any thought on where the issue might be?

Hello they will run very hot ,normal. Tubes will run very hot to the touch. Recs and output tubes tend to run the hottest . Check the tubes if ok then they are fine, you can check both voltage and resistance on the pinns to the rec and output tubes if its ok you should be good to go.Allow plus/minus 20% on readings.Sprman

Yeah hot is normal but these will bring a blister if you try to take one out as soon as you turn it off. I'll check the pine slot and hopefully the rest of capand resistor replacement will cool them down alittle....


Thanks for the info

Hi yes they will blister you.A 6L6 will get very hot as will other recs.Sprman

Got burnt on my arm on a 5U4G rectifier,OUCH! did that hurt for a while! I have seen rectifier tube plates glow red hot bucause or a shorted electrolytic capacitor.

You should never plug something in un restored. You can do alot of dammage real fast. Like destoying the power transformer. Blowing up capacitors.. Etc.....
Be careful!
Bill Cahill

Yeah I know.I got a call from a gentleman that was cleaning out he was clearing out his grandparents house,and wanted to know if I was interested in an old radio.I told him NOT to plug it in to see if it works.Of when I got there he had it turned on.I could see that red hot rectifier tube a mile away!

I'm waiting on a 20k resistor and I'll be done with the chassis rebuild. Went to Radio Shack to see if by change they had one.....what a joke. I can remember a time if you needed electronic parts, RS had it. Now they are only interested in selling batteries and cell service.
So back to the 37-89........I replaced the electr. caps yesterday, put them back in the cans but here's the weird part. The schematic shows 2 separate caps, one 8 mfd, one 12 mfd. These had been changed out at some point because the caps were dated 1956, 1958 but they were both marked 80mfd and when I checked them they were over 90 mfd each. I understand you can bump up maybe 10%, but up to 80mfd.....what were they thinking. Any who, the 8 and 12 are working fine, nothing but the (5Y4) and (6F6) is running hot. Well that is except the 20k resistor that measure 14k and it is a bit warm. Update you when I move on to the next radio. Oh by the way, this radio cabinet has pin striping and man is that a pain.

Don't trust the originals. They will break down, and, cause major dammage.
The replacements must go, also.
A 10 mf, and, a 15 mf would be fine. The others are too high.
Bill Cahill

Correct you are sir, already replaced them.
Do you know a source that ships next day when order caps and such? It seems when I order parts it takes 7 or 8 days to get them. Heck I even expedited and order and it only cut one day off.

Ben Delk wrote:Correct you are sir, already replaced them.
Do you know a source that ships next day when order caps and such? It seems when I order parts it takes 7 or 8 days to get them. Heck I even expedited and order and it only cut one day off.

Perhaps AES. Antique Electronic Supply companny.
More money, though.
Bill Cahill

I have tried them as well. A bit quicker but more money for sure. Thanks

Hey, not to change the subject, but, look in raido forums section. I just posted on an old project. Speaking of buried nightmares!
Bill Cahill