When I was debugging the TC59 mag tape controller on the PDP-9 I found that sometimes the READY signal from the TU20 would not go active. Yesterday the intermittent problem became permanent. The TU20 manual is on Bitsavers (Thanks to the LCM). The ~MOTION signal goes inactive when the tape is moving and goes active when the tape stops. That looks correct. The SETTLING DOWN signal should go active for 5ms, and then go inactive. The SETTLING DOWN signal is always active, so READY never goes active. I measured the voltage drop on all of the transistors and diodes on the R303 is slot A21. All of the measurements look OK. I am not really qualified to debug an R module to the component level, so a replacement module would be really helpful. Does anyone have an R303 flipchip that they would part with? -- Michael Thompson