Some 800B Service Manual Discrepancies

[Joseph W Strickland]

I discovered some 800B Service Manual Discrepancies today. In comparing what was in the AM RF compartment versus the schematic for the Early 800B that I have, the schematic says R4 is a 15K ohm 2 Watt 10% resistor. It is located on the E39 terminal strip that is illustrated on page 52 which shows that R4 is a 5K ohm resistor. Then looking at what is actually in my set R4 is marked as being a 14K resistor (2W obvious from size) 10% tolerance. It is possible that when Scott published the service manual that the 5K ohms shown mounted on E39 (page 52) that the "1" in the description for R4 was cut off when it was printed. I think that is most likely as the schematic and the parts list are in agreement with it being a 15K ohm 2W 10% resistor.

The R4 that was actually installed in my set is marked brow-yellow-orange-silver which would be a 14K ohm 10% resistor, again obviously 2W from its physical size. I suspect that Scott Radio Labs. just substituted a 14K 2W 10% resistor that they had on hand after running out of 15K 2W 10% resistors. Only 1K ohms of resistance difference is not going to make any significant difference in performance. R4 in my set actually measures 11.1K ohms, so it is going to be replaced by a new 15K ohm 2W wire-wound 5% tolerance part.

Joe

[Joseph W Strickland]

As a follow-up, the R4 I mentioned previously turned out to actually be red-yellow-orange-silver which would mean that it would have been a 24K ohm 2W 10% resistor. Its actual measured value was closer to 30K ohms, so I did change it to the 15K ohm 2W 5% wire-wound resistors I had ordered. The schematic showed it being a 15K ohm 2W resistor in both the Early and Late versions of the 800B. A 24K ohm resistor is not any more common than a 14K ohm resistor. I still suspect a substitution made on the assembly line to keep production flowing.

Joe