On eBay, I bought a B&K 467 CRT Tester at a low price. Before I made a bid, I did some research on this model and found an extensive list of CRTs which can be tested with this unit 
.
Included with the unit were the instruction manuals and a circuit diagram with timing waveforms, as well as CRT adaptors for TV sets intended for sale in Australia around the time colour TV was introduced.
Upon inspection after arrival, it needed some work.
Several resistors were out of tolerance, even though they were 5% units, which included R36, R69, R40, R41, R46-R48, R31, R70, R58, R38, R37 and a 1M0 unit on a rotary switch.
D36 and D37 (each 56V) were internally shorted, and were replaced with seven 16V Zener diodes to get the original voltage of 112V, and seven units would be able to dissipate more heat.
There were minor differences in my unit, which included Q1-4 being 2N5551 units, as well as Q5-7 being better-rated BF337 units. Also, the resistors in parallel with most of the neon indicators were 11M units.
The G1 voltage indicator activated under "SET-UP" mode is somewhat inaccurate, even though R19 was OK, and even replacing meter sample and hold capacitors C1-C3 did not help
.
When testing out, I got no Screen (G2) voltage at the output connector; this was caused by a wire pinched between a control and the chassis, causing the wire to become bare and touch the chassis (R43 got hot and made a bit of a smell)
. Fortunately, no damage occured .
Later, I had problems with the Red section of the circuit. Replacing Q1 to Q4 as well as D21 to D23 (and checking pots R49 to R51) did not help , so I decided to compare waveforms of TP1, A, B and C (normal and inverted).
Waveforms B and C (both either normal or inverted) did not check out, so attention was focused on the 7400 chip.
When this chip was about to be removed, a pin was found to be bent and was not in its socket.
Reseating this chip fixed the problem with the Red section .
The solder joints on the rotary switch were also reworked.
Finally, the Heater Voltage indicator was calibrated, as well as the Line Voltage indicator being calibrated with an on-line pure sinewave UPS which had its output measured.
Interestingly, the two patents pertaining to the TriDynamic feature were consecutively numbered (3,961,241 and 3,961,242 (not 3,962,242). This feature made this equipment quick to learn how to use.
C1-C3 across the meters were quite large to hold the pointers steady as possible as the TriDynamic logic switches each colour section.
The one and only valve/tube (a current-production 12BH7A) is used for the Screen (G2) voltage regulator, since there were not enough transistors which can tolerate high voltages (630V) reliably.
I needed a universal CRT adaptor, and I initially considered cutting the leads off a supplied adaptor, but I did not to do this because the tester was supplied with a homemade CR/CA 6 (B&W) plug to CR/CA 7 socket, which the CR/CA 6 plug fitted the CR/CA 5 (colour) adaptor.
The CR/CA 5 adaptor had all of the CRT signals (there was a common G1 and G2 at the tester and adaptor), so the homemade adaptor plug had an extra pin (stiff wire) added to make use of all CRT signals, with lengths of coloured wire corresponding to the circuit diagram connected to the plug, also with IC test clips on the other end.
This homemade universal adaptor is used with the CR/CA 5 adaptor.
.Included with the unit were the instruction manuals and a circuit diagram with timing waveforms, as well as CRT adaptors for TV sets intended for sale in Australia around the time colour TV was introduced.
Upon inspection after arrival, it needed some work.
Several resistors were out of tolerance, even though they were 5% units, which included R36, R69, R40, R41, R46-R48, R31, R70, R58, R38, R37 and a 1M0 unit on a rotary switch.
D36 and D37 (each 56V) were internally shorted, and were replaced with seven 16V Zener diodes to get the original voltage of 112V, and seven units would be able to dissipate more heat.
There were minor differences in my unit, which included Q1-4 being 2N5551 units, as well as Q5-7 being better-rated BF337 units. Also, the resistors in parallel with most of the neon indicators were 11M units.
The G1 voltage indicator activated under "SET-UP" mode is somewhat inaccurate, even though R19 was OK, and even replacing meter sample and hold capacitors C1-C3 did not help
.When testing out, I got no Screen (G2) voltage at the output connector; this was caused by a wire pinched between a control and the chassis, causing the wire to become bare and touch the chassis (R43 got hot and made a bit of a smell)
. Fortunately, no damage occured .Later, I had problems with the Red section of the circuit. Replacing Q1 to Q4 as well as D21 to D23 (and checking pots R49 to R51) did not help
, so I decided to compare waveforms of TP1, A, B and C (normal and inverted).Waveforms B and C (both either normal or inverted) did not check out, so attention was focused on the 7400 chip.
When this chip was about to be removed, a pin was found to be bent and was not in its socket.
Reseating this chip fixed the problem with the Red section
.The solder joints on the rotary switch were also reworked.
Finally, the Heater Voltage indicator was calibrated, as well as the Line Voltage indicator being calibrated with an on-line pure sinewave UPS which had its output measured.
Interestingly, the two patents pertaining to the TriDynamic feature were consecutively numbered (3,961,241 and 3,961,242 (not 3,962,242). This feature made this equipment quick to learn how to use.
C1-C3 across the meters were quite large to hold the pointers steady as possible as the TriDynamic logic switches each colour section.
The one and only valve/tube (a current-production 12BH7A) is used for the Screen (G2) voltage regulator, since there were not enough transistors which can tolerate high voltages (630V) reliably.
I needed a universal CRT adaptor, and I initially considered cutting the leads off a supplied adaptor, but I did not to do this because the tester was supplied with a homemade CR/CA 6 (B&W) plug to CR/CA 7 socket, which the CR/CA 6 plug fitted the CR/CA 5 (colour) adaptor.
The CR/CA 5 adaptor had all of the CRT signals (there was a common G1 and G2 at the tester and adaptor), so the homemade adaptor plug had an extra pin (stiff wire) added to make use of all CRT signals, with lengths of coloured wire corresponding to the circuit diagram connected to the plug, also with IC test clips on the other end.
This homemade universal adaptor is used with the CR/CA 5 adaptor.
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