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Tektronix 7633 Scope, Can anyone please help Old64goat!!!
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finom1:
Is this the Q1195 pinout Bill was talking about not being able to read the numbers?

David Hess:
1. The neon bulbs are used as low leakage low capacitance voltage suppressors between the cathode and other tube elements.  This is the first time I have not seen them included on the schematic.  They will often briefly flash when the instrument is turned on or off.

2. The multiplier could be bad but I do not think we would see the symptoms of zero cathode voltage and an intact fuse if that was the case.  Like I posted earlier, I would disconnect the input to the multiplier until the rest of the board works.

3. The flat black discoloration on the left side of the high voltage multiplier is soot attracted by the high positive electrostatic potential and is completely normal.  All CRTs with PDA (post deflection acceleration) accumulate that to some extent.

4. I was very surprised to see that the layout for the high voltage multiplier is included in figure 8-11.  Tektronix refers to it as A9 - Anode Board.  If the multiplier was bad, then I would build a new one from scratch.

5. The pin numbers shown on the schematic at the 2N3055 from top to bottom are 2, 3, 1 for the molded transformer and 5, 1, 2 for the dipped transformer.  So there must have been two different inverter transformers used.

6. My guess is that two of the pins on the primary side are for the +600 volt DC secondary winding and I am sure that the two brown leads coming out of the top are for the CRT heater winding.

7. The +50 volt marking is for diode CR1216.  The winding shown below it is for the +600 volt DC output and also drives the focus and z-axis restorers with AC.

8. That big red capacitor looking thing under the high voltage multiplier is the reed relay.  The glass envelope can be seen at the ends.  My guess is that it is a high voltage vacuum reed relay but I do not remember ever seeing one before.

9. The CRT circuit schematic includes a partial A8 z-axis amplifier and the A9 anode board.  Their are outlines on the schematic separating the different boards.  Usually at the bottom of each outline, it is marked for which board it applies to.  The original drawing has the board outlines highlighted in blue.

10. There is a TO-92 packaged black plastic transistor with a metallic blue flat between the two metal can transistors you counted.  I think Motorola liked to mark their TO-92 transistors that way.

11. Those vertically mounted boards on the high voltage board must be the focus DC restorer and the z-axis DC restorer.

12. The relay coil is marked K1177 and it is shown below and to the right of the inverter transformer on the schematic.  It is left of the RS HORIZ GAIN adjustment.

13. The high voltage multiplier with part number 152-0682-00 has a date code of 8726 so this oscilloscope was produced sometime after the  middle of 1987 making it one of the last ones.  The 7633 was produced from 1974 to 1990.  The 7623B which replaced it was only made in 1991.

14. The plugs all have pin 1 marked with an arrow on the plastic body and usually a marking on the board.

David Hess:

--- Quote from: finom1 on May 08, 2017, 07:36:54 pm ---Is this the Q1195 pinout Bill was talking about not being able to read the numbers?
--- End quote ---

Yes.  That is actually the pinout for the connector on the board.  Based on the notation, there were two versions of the inverter transformer and they used a different pinout for the connector going to the transistor.

Cyberdragon:
Do the transistors have little white marks on the bottom of the pins? Those are sockets, the transistors pull out.
David Hess:

--- Quote from: Cyberdragon on May 08, 2017, 08:28:09 pm ---Do the transistors have little white marks on the bottom of the pins? Those are sockets, the transistors pull out.
--- End quote ---

I do not know exactly when they changed but late production from Holland did not use the Berg Miniserts found on earlier production.  I have some plug-ins like this and the small signal transistors are soldered into place.

When I am working on these, I remove the transistors and install individual collet pins so the transistor can be replaced without soldering.
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