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  1. dorke

    Hitachi desk fan capacitor replacement

    You can try this one: http://www.ebay.com/itm/CBB61-Model-AC-450V-2uF-2-wire-Terminal-Ceiling-Fan-Motor-Run-Capacitor-Black-/301686335348?hash=item463de82774 Should be cheaper than Amazon. It requires soldering (unlike the original), but will work perfectly and safely.
  2. dorke

    Stereo power amp - odd fault

    Not too odd... Ch A and Ch B are not symmetrical. What are you actually connecting to the inputs? Mono plug Stereo plug? Read about it here http://www.drtube.com/schematics/marshall/8004-8008-hbk.pdf
  3. dorke

    Tektronix 2235 Sweep Generator (horizontal mode) A issue

    Well, It may be possible,certainly worth a try!!! There are limitations of course , like the "dependency" of Time/Div and the sweep time(that we want to observe) etc. First thing before opening the scope, be aware of the presence of fatal voltages and take the required precautions ! Open the...
  4. dorke

    Tektronix 2235 Sweep Generator (horizontal mode) A issue

    You need another scope to be able to find the problem. Have you got one,or can you get one ? I'll be happy to help in tracing the waveforms on the service manual. Look at the "general" trace of a scope added below. I added some lines to explain one possible "A gate" problem that can produce the...
  5. dorke

    Tektronix 2235 Sweep Generator (horizontal mode) A issue

    Well,I don't think it is the CRT since when the fault occurs and you switch to "B only" it will work fine,right? Just to be clear on the issue: If you start with a "cold" scope it works (with Holdff=norm) fine. Then, as the scope warms-up it is deteriorating gradually to intermittent and then...
  6. dorke

    Trying to repair a shaver charger

    The voltage is too high. Can you test the voltage on the +Vo and -Vo of the module itself? Btw,how accurate is your DMM? Try testing a new AA or AAA battery with it.
  7. dorke

    Trying to repair a shaver charger

    This module is a universal AC input,should work fine anywhere on earth. Diodes point o.k cathodes(line mark) away from +Vo. The resistor has no direction, but it does not look like a 2Watts part, more like1/2W: that is not good! N,L :Does your charger have an AC cable? If it does , How many...
  8. dorke

    LED garden lights malfunctioning

    There is a similar device the QX5252F. The E(8pin) version is with Photo-sene input, the F(4 pin) version is without. In order to check the circuit you need a DVM,have you got one? You can find the datasheet here: http://www.mikrocontroller.net/attachment/158139/QX5252.pdf It can be bought...
  9. dorke

    LED garden lights malfunctioning

    These usually are operated (on/off) using a Photosensitive device. Isn't there one on the unit?
  10. dorke

    Tektronix 2235 Sweep Generator (horizontal mode) A issue

    It looks like there is an issue with the "HoldOff" and it is related to A triggering. Can you try this: A only. A trig source=INT(and select the CH. you are using). A trig=auto. Holdoff=normal. A/B per division "unified" in a position to show 4 cycles or more on the screen. B delayed= 0,0...
  11. dorke

    Tektronix 2235 Sweep Generator (horizontal mode) A issue

    Regarding the trigger I would also test these cases, in A only . Is there any influence of the following: 1.the "hold off" knob 2.the A trig slop 3.the trig level knob in "normal trig mode" The following regards the A/B sweeps In ALT: 1.Are the "A/B intensity" knobs functioning? 2.Is the "A/B...
  12. dorke

    Tektronix 2235 Sweep Generator (horizontal mode) A issue

    I can not see the video it says: "Sign in to view..."
  13. dorke

    Tektronix 2235 Sweep Generator (horizontal mode) A issue

    First, I would eliminate the case of a triggering fault in A mode : Try it in A only mode. Check if you can make it trigger and get a steady signal on the CRT. I mean try all possible A triggering settings(including external,if possible)and playing with the trigger level knob. Do you get the...
  14. dorke

    Tektronix 2235 o-scope power supply smoke

    I watched the clips but could not understand what is the problem. In the clips you keep working the knobs without saying what you are doing,and what seems to be the problem. Could you explain in words?
  15. dorke

    Cassette player: cannot locate where to connect the wire

    The left drawing shows the place to connect the flat crimp terminal to a metal spade. Like Martaine says it is chassis ground.
  16. dorke

    refrigerator causes power surge

    At Fios, Not at all, Electrical wiring in houses should only be done by a qualified electrician . Thanks for the Gaelic explanation, and,I finally chose an electrifying Avatar...
  17. dorke

    refrigerator causes power surge

    At fios, That goes without saying,but a good thing to remind the unaware... Btw, Some explanations about your Gaelic nick-name ?
  18. dorke

    refrigerator causes power surge

    Well, first thing to do is change the outlet that causes the sparks. If it is an external "splitter" ,remove it. If it is "in the wall ",open it and inspect it: Look for over-heating/loose screws etc. if you find any replace it as well. While at it inspect the wires: they should be the...
  19. dorke

    refrigerator causes power surge

    Could also be a "dieing" compressor start-up capacitor. It is probably causing a too high start-up current. If you look at a regular incandescent light bulb (preferably on the same circuit as the frig) you can clearly see it dim for a very short time on startup.
  20. dorke

    Memory investigation on an HP35665A and bad desoldering

    Yes, those ground plains(and power plains) are a big problem. In this case maybe a combination of sucking only them first, and then using the hot gun for the rest to pull the chips out. Another "brutal", but effective way . is to cut the sip chips with a good cutter and pull the pins out one by...
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