Greetings,
I have just started a restoration on a American Bosch 595P Centr-O matic. http://www.nostalgiaair.org/resources/331/M0022331.htm

First issue so far is a (diagram # 16) resistor valued at 5000 ohm 1/4 watt in parallel with a .05 condenser (diagram # 15). The resistor measures 6400 ohms and will be destroyed anyway because it's wrapped so tight within a set of coils (6A8 section). I have (from Radioshack) a 4700 ohm 1/2 watt and a 6800 ohm 1 watt from just radios.
If the 6800 is out of tolerance by more than 30%, would the 4700 undervalued be within tolerance and safe? The working space within the set of coils is very small and don't want to order a minimum for 1 resistor.
Thank you,
Vinny A.

Hi Vinny

Use 4700 ohm resistor. It's within tolerance (6%)and is a replacement for 5000 ohms.

Norm

:Greetings,
:I have just started a restoration on a American Bosch 595P Centr-O matic. http://www.nostalgiaair.org/resources/331/M0022331.htm
:
:First issue so far is a (diagram # 16) resistor valued at 5000 ohm 1/4 watt in parallel with a .05 condenser (diagram # 15). The resistor measures 6400 ohms and will be destroyed anyway because it's wrapped so tight within a set of coils (6A8 section). I have (from Radioshack) a 4700 ohm 1/2 watt and a 6800 ohm 1 watt from just radios.
:If the 6800 is out of tolerance by more than 30%, would the 4700 undervalued be within tolerance and safe? The working space within the set of coils is very small and don't want to order a minimum for 1 resistor.
:Thank you,
:Vinny A.
:
:

:Hi Vinny
:
: Use 4700 ohm resistor. It's within tolerance (6%)and is a replacement for 5000 ohms.
:
:Norm
:
::Greetings,
::I have just started a restoration on a American Bosch 595P Centr-O matic. http://www.nostalgiaair.org/resources/331/M0022331.htm
::
::First issue so far is a (diagram # 16) resistor valued at 5000 ohm 1/4 watt in parallel with a .05 condenser (diagram # 15). The resistor measures 6400 ohms and will be destroyed anyway because it's wrapped so tight within a set of coils (6A8 section). I have (from Radioshack) a 4700 ohm 1/2 watt and a 6800 ohm 1 watt from just radios.
::If the 6800 is out of tolerance by more than 30%, would the 4700 undervalued be within tolerance and safe? The working space within the set of coils is very small and don't want to order a minimum for 1 resistor.
::Thank you,
::Vinny A.
::
::
:
:
Thanks Norm, your always on the money.

One other problem: there is a dog-bone resistor (part # 86), Red body, Green end, and a Yellow dot which by color code is 250k, the one in the radio measures 336k. However on the schematic it says 1/2/meg. Am I to assume that there was a change in the radio after the repair manual was created? Or should I go with what the schematic says? The resistor has one end that has a minor coil like twist with some solder on it, but the entire radio does not look like it was tampered with. I have not plugged this radio in yet as I am ordering caps and resistors as needed.
Thank you,
Vinny A.

The resistor in question should be the same value as part number 93. Check the color code on this resistor and replace both if off tolerance.

:The resistor in question should be the same value as part number 93. Check the color code on this resistor and replace both if off tolerance.
:

Warren, thank you for responding. I a little confused as to the replacement. There both out of tolerance, should I go by the schematic value or should I go by what's in the radio? The value for each on the schematic is 1/2 meg but the color coded resistors in the radio by chart are 250k.

Vinny A.

In this case I would go by the color code of what's in the radio now. Both of the resistors did clime up a bit in value. I don't think the values are all that critical in this circuit, as long as both resistors are the same value.

:In this case I would go by the color code of what's in the radio now. Both of the resistors did clime up a bit in value. I don't think the values are all that critical in this circuit, as long as both resistors are the same value.
:

Warren, thanks again. I have only a radio shack 270k 1/2 watt that I will be using. Not exact but within tolerance (as to what's inside the radio). This is the oldest and by far the most complicated radio that I have worked on and I am only just starting it, even the solder on the lugs is like a rock to get through.
I noticed that some of the values of resistors you can not even buy. So let me ask a couple of questions: Is it better to be within +/- tolerance or to put some resistors in parallel to achieve the desired "0" tolerance value? And, why are there different values in the radio (which looks original) vs the schematic? would it maybe have been a production change on the fly or a dollars and cents thing post depression?
Thank you again,
Vinny

Radio manufactures would sometimes use what they had in stock. In the design of the radio a lot of the parts can be wide in the values chosen. It is most likely the schematic does show the correct values that could be used. In more sensitive areas of the radio such as the oscillator, RF and IF the values do need to be close. I would go by the color codes of the original parts. Try and keep the values as close as you can. Being plus or minus within 10% or so of the original values should be fine.