This is my own personal tester, I have owned and used it for about 5 years. About 2 years ago, I gave it a once over. The main power resistor was replaced, the voltages tested & adjusted. I remarked the shunt dial as stated in the re-calibration instructions. The bias needs to be about 2 "points" lower then recommended to get a correct reading.
I hate to use the word re-calibrated, however these adjustments were done against a 6L6 tube with readings from a known tester/seller. I have tested and sold hundreds of tubes with this tester without a hitch or complaint!
Overall condition is very good, the picture of the outside case shows the worst side. The roll chart is smooth. The original manual is included, all other charts are available online.
Feel free to ask any questions, you can call or text me at 727-423-4108.