09-07-2020, 10:59 AM
09-07-2020, 08:10 PM
Found several 6AL5 in my stash. A couple tests like new.
But...after the second pins' scraping the original one also tested OK. Borderline but hey, it is a diode, it usually works fine even below borderline.
But...after the second pins' scraping the original one also tested OK. Borderline but hey, it is a diode, it usually works fine even below borderline.
09-08-2020, 07:20 PM
It seems the radio employs a multitude of paper caps. Or they look to me like paper caps, so I decided to check.
Here is 3,300pF cap being measured out of circuit.
[attachment=23005]
[attachment=23006]
The one marke 0.015uF is 0.059uF.
So it seems like a recap is in order. I was hoping to avoid that.
Those brown plastic-molded ones are also way up. About x2. The paper-looking ones are x4.
Here is 3,300pF cap being measured out of circuit.
[attachment=23005]
[attachment=23006]
The one marke 0.015uF is 0.059uF.
So it seems like a recap is in order. I was hoping to avoid that.
Those brown plastic-molded ones are also way up. About x2. The paper-looking ones are x4.
09-08-2020, 07:57 PM
Mike, the Grundig 3198 I restored last spring had 25 paper caps and all were very leaky or way out of tolerance. Most of the caps were ERO and are notorious for this condition. Of course, paper caps that are 60 years old are expected to be deteriorated. Ironic for the Grundig name, you'd think a few would be good.
Rod
Rod
09-08-2020, 08:36 PM
Rod, yes, ERO caps.
All gone.
Before
[attachment=23007]
Extracted
[attachment=23009]
After
[attachment=23008]
This is just one compartment. There are many more.
The testament to the leakiness is this cap:
0.033uF
[attachment=23010]
Measures this:
[attachment=23011]
0.33uF, that is exactly 10 times more. Imagine what leakage causes this.
With this kind of leakage AND weakening tubes, I could only imagine why this radio was never played for the last 30 or more years.
The electrolytic cap (2x100uF, 375V) is soldered and screwed under the transformer, so....no good access - will have to remove the transformer, possibly.
All gone.
Before
[attachment=23007]
Extracted
[attachment=23009]
After
[attachment=23008]
This is just one compartment. There are many more.
The testament to the leakiness is this cap:
0.033uF
[attachment=23010]
Measures this:
[attachment=23011]
0.33uF, that is exactly 10 times more. Imagine what leakage causes this.
With this kind of leakage AND weakening tubes, I could only imagine why this radio was never played for the last 30 or more years.
The electrolytic cap (2x100uF, 375V) is soldered and screwed under the transformer, so....no good access - will have to remove the transformer, possibly.
09-09-2020, 09:08 PM
I keep extracting caps. It looks like every single cap except tube ceramics will be replaced as they all exhibit x4 to x8 upward drift. This is promissing to become the largest recapping job so far for me.
Some caps are under the output transformer, so I had to extract it; no small effort.
But it will afford me the chance to also replace the filter electrolytic, plus some real long slim axial one, plus some paper ones.
[attachment=23012]
[attachment=23013]
There are some caps I had to parallel: 0.068uF became the 0.022+0.047, or 0.15uF = 0.1+0.047.
Most caps are soldered in such a way that they come out easy. But a couple had the leads looped.
Some caps are under the output transformer, so I had to extract it; no small effort.
But it will afford me the chance to also replace the filter electrolytic, plus some real long slim axial one, plus some paper ones.
[attachment=23012]
[attachment=23013]
There are some caps I had to parallel: 0.068uF became the 0.022+0.047, or 0.15uF = 0.1+0.047.
Most caps are soldered in such a way that they come out easy. But a couple had the leads looped.
09-10-2020, 08:53 PM
Removed the twistlock cap.
It is a dual electrolytic 2x100uF, 350V WV.
It also has raised leads panel, as the opening in the chassis is small and were it not for the panel being raised, the leads rivets that hold them to the panel would be touching the chassis.
I doubt this exists as exact fit. Ordering from Hayseed is an option if they could replicate it to it exactness.
Or.....restuffing.
Surprisingly the caps measure about right but the measurements fluctuate, and I am reluctant re-using it the way it is, considering what it takes to extract it should something go wrong.
[attachment=23015]
[attachment=23016]
There is that
https://www.tubesandmore.com/products/ca...v-100100-f
But I have to see the twist tabs and connections drawings before I could decide.
It is a dual electrolytic 2x100uF, 350V WV.
It also has raised leads panel, as the opening in the chassis is small and were it not for the panel being raised, the leads rivets that hold them to the panel would be touching the chassis.
I doubt this exists as exact fit. Ordering from Hayseed is an option if they could replicate it to it exactness.
Or.....restuffing.
Surprisingly the caps measure about right but the measurements fluctuate, and I am reluctant re-using it the way it is, considering what it takes to extract it should something go wrong.
[attachment=23015]
[attachment=23016]
There is that
https://www.tubesandmore.com/products/ca...v-100100-f
But I have to see the twist tabs and connections drawings before I could decide.
09-11-2020, 07:43 PM
[attachment=23032]
This represents about 2/3 of what is there.
Not counting the electrolytics.
There are a few polyester caps, they are ok.
EVERY SINGLE paper cap is SUPERBAD. The drift upwards is up to 10x in some.
This represents about 2/3 of what is there.
Not counting the electrolytics.
There are a few polyester caps, they are ok.
EVERY SINGLE paper cap is SUPERBAD. The drift upwards is up to 10x in some.
09-12-2020, 09:18 PM
09-13-2020, 06:05 PM
Today I extracted all 4 other electrolytics, all axial.
One of them, the 10uF 350V, is RIGHT ON THE MONEY. I almost regretted taking it out. But......it is 62 years old. Time to go.
I ordered the 6 pieces I need from Mouser.
The cap from the crossover is an enigma. It is the same thing as we had in 38-690 with that 1uF cap.
The cap IS a polarized electrolytic, 20uF 30/40V. With "+" clearly shown.
I am not sure how this works with no problem but this is one of 2 or 3 electrolytics that is still tests well. And, yes, I am changing it - I am leaving no cap unturned except the polyesther (very few of these, the rest is paper and all are bad) and tubular ceramics.
So, I unsoldered this cap, that is unusually large for its parfameters, and measured it on my LCR meter (Standford Research) in "C+R" mode to see the ESR.
It is very surprising, the ESR drops to 0.06 Ohm at 10kHz, being about 3 Ohm at 100Hz.
The high-ripple 20uF 450V cap by Panasonic (almost 700 ma ripple) I usually use for my restorations as he rectifier filter, shows about 1 Ohm with little variations across the frequency range. Which made me decide against it in the crossover.
I only had one other electrolytic (new) actilng like this, namely Non-pol from Parts Express, the 100uF; the rest have much higher ESR.
So, I chose to use a film cap, 20uF 250V. Those can take high current and have very negligible ESR, and I do not have to think up the theory how a polarized cap works in pure AC curcuit. An expensive SOB, they start at about $8. I mean, there are those $4 apiec from China....But I prefer Illinois cap from Mouser: wherever it is made, it is a reputable name.
So.....meantime I have to cut open the big can for which I ordered two 100uF 400V caps to restuff. Hayseed will quote but I imagine the price, especially the very special one like this, with the raised panel, will cost too much, and me being accustomed to restuff big cans, that us a sheer waste.
One of them, the 10uF 350V, is RIGHT ON THE MONEY. I almost regretted taking it out. But......it is 62 years old. Time to go.
I ordered the 6 pieces I need from Mouser.
The cap from the crossover is an enigma. It is the same thing as we had in 38-690 with that 1uF cap.
The cap IS a polarized electrolytic, 20uF 30/40V. With "+" clearly shown.
I am not sure how this works with no problem but this is one of 2 or 3 electrolytics that is still tests well. And, yes, I am changing it - I am leaving no cap unturned except the polyesther (very few of these, the rest is paper and all are bad) and tubular ceramics.
So, I unsoldered this cap, that is unusually large for its parfameters, and measured it on my LCR meter (Standford Research) in "C+R" mode to see the ESR.
It is very surprising, the ESR drops to 0.06 Ohm at 10kHz, being about 3 Ohm at 100Hz.
The high-ripple 20uF 450V cap by Panasonic (almost 700 ma ripple) I usually use for my restorations as he rectifier filter, shows about 1 Ohm with little variations across the frequency range. Which made me decide against it in the crossover.
I only had one other electrolytic (new) actilng like this, namely Non-pol from Parts Express, the 100uF; the rest have much higher ESR.
So, I chose to use a film cap, 20uF 250V. Those can take high current and have very negligible ESR, and I do not have to think up the theory how a polarized cap works in pure AC curcuit. An expensive SOB, they start at about $8. I mean, there are those $4 apiec from China....But I prefer Illinois cap from Mouser: wherever it is made, it is a reputable name.
So.....meantime I have to cut open the big can for which I ordered two 100uF 400V caps to restuff. Hayseed will quote but I imagine the price, especially the very special one like this, with the raised panel, will cost too much, and me being accustomed to restuff big cans, that us a sheer waste.
09-13-2020, 07:22 PM
Mike, Wow You are making progress.. I have decided to stop doing anything on the one I have.. Due to the Rust on the push button assembly.. I cannot even get the power on to stay in the on position..
No way I could take the assembly out to many wires to disconnect..
So good luck with yours ..
Skip
No way I could take the assembly out to many wires to disconnect..
So good luck with yours ..
Skip
09-13-2020, 08:32 PM
Skip,
Yeah, this one is a beast.
Sorry about yours.....you sure there are no penetrating things that could somehow dissolve the rust without having to extract the whole thing out?
Yeah, this one is a beast.
Sorry about yours.....you sure there are no penetrating things that could somehow dissolve the rust without having to extract the whole thing out?
09-13-2020, 09:24 PM
Well i tried a few.. However I do not think the rust is stopping the buttons from working.. they will not latch or release properly.. but maybe it is..
Skip
Skip
09-13-2020, 10:24 PM
The mechanics there is quite intricate.
For instance, the FM button will act as the gear shift and will switch the rotation from the AM bands pointer and the tuning cap to the FM band pointer and the FM tuning cap.
I will also need to lube mine: I stopped the shaft from making a squeaking sound, but need to lube the levers to make switching a bit more...silky
Well, it is good then if you hadn't started recapping as the mounting of the components is pretty involved: this is not your Philco 70 with an inch of space on each side of each component. This one is a cobweb. Closer to Transoceanics but even denser.
For instance, the FM button will act as the gear shift and will switch the rotation from the AM bands pointer and the tuning cap to the FM band pointer and the FM tuning cap.
I will also need to lube mine: I stopped the shaft from making a squeaking sound, but need to lube the levers to make switching a bit more...silky
Well, it is good then if you hadn't started recapping as the mounting of the components is pretty involved: this is not your Philco 70 with an inch of space on each side of each component. This one is a cobweb. Closer to Transoceanics but even denser.
09-17-2020, 09:54 PM
Capacitors came in yesterday - Mouser continues free upgrading of USPS to UPS Blue.
So I finished all except the main cap, which I cut open today and it is being soaked in vinegar to neutralize whatever it is there to neutralize.
Then it will receive two high ripple 100uF 400V caps.
Then I pray God I remember how all was connected - the photos should help - and then I have to re-install the output transformer.
So I finished all except the main cap, which I cut open today and it is being soaked in vinegar to neutralize whatever it is there to neutralize.
Then it will receive two high ripple 100uF 400V caps.
Then I pray God I remember how all was connected - the photos should help - and then I have to re-install the output transformer.