The quality of the electron beam in electron defraction tube S (1013889) is affected by the resistance between sockets C5 (cathode) and F4 (heating filament) on the tube. For optimum results, the resistance needs to be 390 kΩ. Tube holder S (1014525) is accordingly designed such that this resistance is present.
Older designs feature a much smaller resistance and need to be modified in order to work with the new S-series electron deflection tube 1013889).
Tube holders affected: U18500, U185001, 1000610
![Replacement Circuit Board for Tube Holder S, 4008573 [U99999-611], 电子管S](/imagelibrary/U99999-611/U99999-611_01_Replacement-Circuit-Board-for-Tube-Holder-S.jpg)
![Teltron 管座 S, 1014525 [U185002], 电子管 S](/thumblibrary/U185002/U185002_01_140_140_Teltron-管座-S.jpg)
![电子衍射试管, 1013889 [U185711], 电子管S](/thumblibrary/U185711/U185711_01_140_140_电子衍射试管.jpg)
![Teltron亥姆霍兹线圈S, 1000611 [U185051], 电子管S](/thumblibrary/U185051/U185051_01_140_140_Teltron亥姆霍兹线圈S.jpg)
![汤姆生试管, 1000617 [U18555], 电子管S](/thumblibrary/U18555/U18555_01_140_140_汤姆生试管.jpg)
![演示用的电子束偏转管, 1000651 [U19155], 电子管D](/thumblibrary/U19155/U19155_01_140_140_演示用的电子束偏转管.jpg)
![高压电源5kV(115 V, 50/60 Hz), 1003309 [U33010-115], 供电器](/thumblibrary/U33010-115/U33010-115_01_140_140_高压电源5kV-115-V-5060-Hz.jpg)