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Old 20th Apr 2020, 12:45 pm   #161
ms660
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Default Re: Kolster Brandes 666 Valve radio restoration.

Quote:
Originally Posted by Station X View Post
Read Lawrence's post #128. You don't need to test the heater pins. Don't forget the top caps.
Just to note, the base types I gave for the valves circuit refs were those shown in the service sheet, not sure what's in the OP's receiver, some valves of the same electrical type were made with B5 or B7 bases.

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Old 20th Apr 2020, 12:45 pm   #162
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Default Re: Kolster Brandes 666 Valve radio restoration.

The heater pins for V1, V2, V3 & V6 are pins 3 & 4
o.k will continue to test except for heater pins 3&4
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Old 20th Apr 2020, 1:14 pm   #163
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Default Re: Kolster Brandes 666 Valve radio restoration.

Tested V3 Acquired following results :-

Pin 2 Volt meter set at 2V Reading of -.013V

Pin 5 Volt meter set at 2V Reading of 0.344V

Pin 1 Reading of 36V

pins 3/4 heater pins not testeed

Cap pin of valve Reading of 77V
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Old 20th Apr 2020, 1:25 pm   #164
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Default Re: Kolster Brandes 666 Valve radio restoration.

Pin 1. Screen grid. 36 VDC. Low.
Pin 2. Control grid. -0.013 VDC. OK.
Pin 5. Cathode. 0.344 VDC. Low.
Top cap. Anode. 77 VDC. Low.

Anode voltage is well down. Could be down to leakage in C18.
Screen grid volatge is well down. Could be down to leakage in C12.
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Old 20th Apr 2020, 1:51 pm   #165
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Default Re: Kolster Brandes 666 Valve radio restoration.

Tested V2 acquired following results :-

Pin 2 Volt meter set at 2V Reading the reading found to be flucturating a little between reading values of .050V to .070V

Pin 5 Volt meter set at 2V Reading of 0.52V


Pin 1 reading of 27V

Pins 3/4 not tested

Valve Tube Cap acquired a reading of 73V
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Old 20th Apr 2020, 1:57 pm   #166
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Default Re: Kolster Brandes 666 Valve radio restoration.

Low anode voltage again. Could also be down to C18 being leaky. I reckon you'll find the same with V1.
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Old 20th Apr 2020, 2:17 pm   #167
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Default Re: Kolster Brandes 666 Valve radio restoration.

V1 tested acquired following results :-

Pin 2 Volt meter set at 2V acquired reading of 0.48V

Pin 5 Volt meter set at 2V acquired reading of .070V

Pin 3 acquired reading of 21V

Pins 4/5 not tested

Cap pin of valve Reading of 74V
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Old 20th Apr 2020, 2:20 pm   #168
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Default Re: Kolster Brandes 666 Valve radio restoration.

Same again. Low anode and screen voltages. Should improve once capacitors have been changed.

Test the resistors next.
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Old 20th Apr 2020, 2:25 pm   #169
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Default Re: Kolster Brandes 666 Valve radio restoration.

O.K ,
Will turn set upside down and go through and make note 0f all values of
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Old 20th Apr 2020, 2:42 pm   #170
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Default Re: Kolster Brandes 666 Valve radio restoration.

Just had at look at C18 , solder joint dont look to briliant as quite old (wondering possible dry solder joint could cause low readings )
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Old 20th Apr 2020, 2:56 pm   #171
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Default Re: Kolster Brandes 666 Valve radio restoration.

No. A poor solder joint won't cause a capacitor to become electrically leaky.
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Old 20th Apr 2020, 4:04 pm   #172
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Default Re: Kolster Brandes 666 Valve radio restoration.

Been checking the resistances done along the one side , my vault meter must have different hms settings as need to multiply the results to correspond with data of W/S service manual
Result Along 1 side of chasis

(some differ a bit)


R1 is definatly low 49,000 LOW (appears may be cracked halfway along)
R2 67,000 (bit low)
R3 75,000
R4 268,000
R5 262,000
R6 110,00O
R7 110,000 (Appears also quite low)
R8 10,000
R9 29,000
R10 13,000
R11 8.000
R12 3,000 (LOW)
R13 3,000
R14 586
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Old 20th Apr 2020, 4:54 pm   #173
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Default Re: Kolster Brandes 666 Valve radio restoration.

Just a quick note; I have found that KB during this era used wire wound resistors quite frequently and these are often quite close to the original value.
Measuring the resistors whilst connected in circuit may produce some erroneous results because of influences from other components in the circuit. This will generally make the measured value appear lower than it should.
In general terms any carbon composition resistors will tend to go high in value with age.

So don't go chopping them out unnecessarily just yet.

Mike

Last edited by crackle; 20th Apr 2020 at 5:05 pm.
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Old 20th Apr 2020, 5:06 pm   #174
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Default Re: Kolster Brandes 666 Valve radio restoration.

Looking at the measurements so far;-

R1 out of spec.
R7 out of spec.
R11 just in spec.
R12 out of spec.

R1 is definitely not shunted DC wise, so I believe the reading to be correct.

R7, R11 and R12 are all in the power supply area and I'm not sure whether they're shunted DC wise or not.

If R12 is out of spec it will have a profound effect on circuit voltages around V1, V2 and V3 which we know are incorrect. I suggest disconnecting one end of it and then checking it again.
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Old 20th Apr 2020, 5:59 pm   #175
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Default Re: Kolster Brandes 666 Valve radio restoration.

Managed to check the rest very hard to get at a couple

R15 260,000
R16 234,000
R17 300
R18 3000
R19 387
R20 512,000
R21 582
R22 250,000
R23 getting no reading
R24 40,000 LOW
R25 4135
R26 250,000
R27 135,000
R28 135,000
R29 Unable to find

Think i have worked it out correctly but not 100% certain as my vault meter scale is different and need to multiply
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Old 20th Apr 2020, 6:18 pm   #176
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Default Re: Kolster Brandes 666 Valve radio restoration.

just quickly Re-checked R12 Getting reading of 18,000 now still in sittue bit better (spec should be 25,000)
bit better possible had bad connection before , will unsolder and recheck again
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Old 20th Apr 2020, 6:27 pm   #177
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Default Re: Kolster Brandes 666 Valve radio restoration.

R12 unsoldered from mounting now getting a reading of 20,000 (still a bit low) to spec
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Old 20th Apr 2020, 6:43 pm   #178
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Default Re: Kolster Brandes 666 Valve radio restoration.

Thank you for your help today ,
possibily do some more test tomorrow
(have just quickly re-checked R7 again incase i read it faulty or of bad connection still appears low reading )and possibly will continue tomorrow and double check the faulty readings plus any other tests may need doing
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Old 20th Apr 2020, 7:26 pm   #179
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Default Re: Kolster Brandes 666 Valve radio restoration.

Hi
I do have a box full of new resistors all different types ,have attached picture of , but possibly not suitable for this radio but may aswell just check
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Old 20th Apr 2020, 9:15 pm   #180
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Default Re: Kolster Brandes 666 Valve radio restoration.

It's not always possible for me to respond quickly, I have my own stuff to do as well. Some times I can interrupt this, but not today.

R12 is just in spec.

R23 no reading. This is a 2Mohm resistor which is the highest value your meter can measure. There's no way of telling whether it's drifted high or not.

R24 is shunted by L4. I'm surprised that the reading is so high. I'd have expected it to be quite low. The reading between L4 points D and E is quoted as 57 ohms.

R27 and R28 are shunted by L5, so effectively wired in parallel. Expected reading is 125k, so 135k is OK.

R29. This should be connected to the centre tag of the volume control.

The time has come when you can't do much more without replacing components.

The resistors could be useful if they're the correct values and you don't mind them being physically small when compared to the originals.
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