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I¡¯ve come quite a long way into repairing this early 547. All the TD¡¯s are replaced and working properly, all the electrolytics have been replaced, a few out-of-spec resistors have been replaced too, as well as a few transistors, mainly the AF118. I had ordered a few AF118 (4.5€ a pop), but those that arrived were not the regular TO-7. They were instead in a TO-92 package. If you see those, don¡¯t even bother, they don¡¯t work as expected. I returned them and did find the proper NOS TO-7 ones that worked right off the bat as expected, albeit a bit pricier at 5.8€ a pop!
Anyways, the problem I¡¯m facing concerns the horizontal amplifier. For starters, the trace is always moving a bit right and left. Also, it is just impossible to adjust the timing. It¡¯s completely off even with the X1 and X10 all the way CCW. It¡¯s still way to wide. I replaced what I found to be out of spec, but there is still no change.
I haven¡¯t measured the 30K and 18K 8W precision resistors though¡­

Here¡¯s a short video of a 1KHz from a Type 184. You can clearly see the trace moving right and left, as well as the timing being off, and I can¡¯t adjust it any further.



Any help would be appreciated.

Anyone???

On Fri, Apr 29, 2022 at 07:34 PM, Stephen wrote:

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Anyways, the problem I¡¯m facing concerns the horizontal amplifier. For
starters, the trace is always moving a bit right and left. Also, it is just
impossible to adjust the timing. It¡¯s completely off even with the X1 and
X10 all the way CCW. It¡¯s still way to wide. I replaced what I found to be
out of spec, but there is still no change.
I haven¡¯t measured the 30K and 18K 8W precision resistors though¡­

Hi Stephen,

[I didn't (re)read the whole previous repair story.] Are you sure now that the sweep generator itself is not the problem? If A and B sweeps show the same problem then the problem is likely further on in the horizontal chain. To be sure you can use another scope with 10X probe to observe the waveform at the "A Sweep" front panel bus. That signal immediately follow the Miller circuit. In my 547 the sweep duration is about 10.5 ms (as should be) with amplitude about 90 V while the dead time between sweeps is about 2 ms. That's with the 547 at 1 ms/div and VAR in calibrated position, fully CW. The sweep time increases (up to 2.5X or so) when VAR is rotated CCW.

Here¡¯s a short video of a 1KHz from a Type 184. You can clearly see the
trace moving right and left, as well as the timing being off, and I can¡¯t
adjust it any further.

Any help would be appreciated.

Albert