Reparation Hameg HM604-2 - Page 1
Forum section: electronics / repair

author: skopg
author_rank: Contributor
timestamp: July 29, 2023, 07:38:40 am
content: Good evening everyone, II am new and new to electronics...I come to you because I have 1 Hameg HM 604-2, and it does not work anymore... I explain I turn on there is a signal on the screen (horizontal line that I can only move in X), if I switch Off Search Delay on Del TRIG there too the lamp lights up (photo1).If I test a component, there is the L-shaped signal on the screen, juntion BC or even in the M17 604-2 manual (photo2).But if I turn or press any button NOTHING happens...Can you help me and tell me what component(s) need to be changed?Thank you for your feedback.

author: RAPo
author_rank: Super Contributor
timestamp: July 29, 2023, 08:19:52 am
content: Set knobs to default position as described in the manual:-all pushbuttons in out position-the three knobs for variable control with the white arrow to calibrated/dent position-all knobs with markers to mid position (vertical up)-level knob on left stop AT-the 3 lever switches to upper most position-coupling switches for chI & Ch.II to GNDAdjust Y-pos.i an d x.pos to center the trace.Report back.set channel I to AC couplingapply the test signal to channel 1Please report back what you'll get on the crt.

author: skopg
author_rank: Contributor
timestamp: July 29, 2023, 04:18:22 pm
content: Hello,I come back to you after doing what you asked me to do.On photo1 start-up, on photo2 after 10 sec; Pressed the button on channel 1, set pos Y and X.Then switched to AC (the signal does not move), but if I restart the button of Channel1 ...There the signal goes up a box (photo3).Thank you for telling me what to do next.ElectroniquementVôtreSkopg

author: skopg
author_rank: Contributor
timestamp: July 29, 2023, 04:45:39 pm
content: Hello, I come back to you after doing what you asked me to do.On photo1 start-up,on photo2 after 10 sec; Pressed the button on channel 1, set pos Y and X.Then switched to AC (the signal does not move), but if I restart the button of Channel1 ...There the signal goes up a box (photo3).Thank you for telling me what to do next.electroniquementvôtre

author: RAPo
author_rank: Super Contributor
timestamp: July 29, 2023, 04:59:23 pm
content: We are making progress.Could you explain what "but if I restart the button of Channel1" is? Which button did you press?Is the trace in AC coupling with or without a signal applied? In photo 3 it looks like there is no signal applied to channel 1.Could you please set the red buttons with the white triangle to a calib/dent setting? The arrow has to point to the right.Also please turn the hold button completely clockwise.Set the channel I to .1V/div, time base to 0.2ms and AC coupling.Set your probe on x10 and pick up the signal from the cal. 2V port.Do you see a square wave with the upper part at the first upper division (and the lower part at the first lower division) with the square wave in the horizontal middle?

author: skopg
author_rank: Contributor
timestamp: July 29, 2023, 06:49:10 pm
content: Re,when I say "I restart button 1", it means that I took it out.The trace in the AC coupling, a line remains in the center, when I take out the button of channel1 the signal goes up a square.According to what you asked it appeared two lines, and after a few seconds a square signal came going from left to right and then, again the 2 lines.

author: RAPo
author_rank: Super Contributor
timestamp: July 30, 2023, 06:57:36 am
content: Thanks, this looks good.Please keep the AC coupling and only show+trigger on channel I settings.I expected more distance on the lines, but I can see where it comes from: you have 1V/div, I asked for 0.1V/div. No problem.Could you please use the 0.1V setting?With this setting, can you shift the trace up/down with Y.Pos I knob?can you shift left/right with the X.pos knob?What worries me is that there is no trigger lock. That will be the next point of investigation.

author: skopg
author_rank: Contributor
timestamp: August 04, 2023, 06:59:17 am
content: Hello,fit after this little break... That's what I did.

author: skopg
author_rank: Contributor
timestamp: August 04, 2023, 07:03:25 am
content: Hello, fit after this little break...That's what I did.Yes I can move up and down and also from left to right

author: RAPo
author_rank: Super Contributor
timestamp: August 04, 2023, 07:19:02 am
content: and it seems that the scope is also triggering!So what is the problem now?

author: skopg
author_rank: Contributor
timestamp: August 04, 2023, 07:36:01 am
content: You talked to me: What worries me is that there is no trigger lock.This will be the next point of inquiry.What should I do now.

author: RAPo
author_rank: Super Contributor
timestamp: August 04, 2023, 10:22:04 am
content: Well, I see that the scope is triggering: the led next to 'TRIG' is lit.So you now have a scope that is working on channel 1 (it shows a trace that can be moved vertically and horizontally and the trace is triggered) that is quite a better situation than we started with ("I explain I turn on there is a signal on the screen (horizontal line that I can only move in X), if I switch Off Search Delay on Del TRIG there too the lamp lights up").You could test if channel 2 is working (do the same as above, but then for channel 2), but I guess it will be oke. Do you have any more concerns?

author: skopg
author_rank: Contributor
timestamp: August 04, 2023, 12:23:50 pm
content: RE,I'm doing this for channel 2: (Set channel 2 to .1V/div, the timebase to 0.2ms and AC pairing.Set your probe to x10 and pick up the signal from the cal port. 2V).And I will keep you informed of the situation.

author: RAPo
author_rank: Super Contributor
timestamp: August 04, 2023, 12:43:14 pm
content: and be sure to press the ChI/ChII button this time ;-)

author: skopg
author_rank: Contributor
timestamp: August 04, 2023, 03:35:05 pm
content: I forgot on T344 I have 0.760mv (not easy to access).Redo on channel2 (I pushed on CH I/II), ok but the Trigger lamp does not light up.I put back on channel 1 and the Trigger also does not light up???

author: skopg
author_rank: Contributor
timestamp: August 04, 2023, 03:39:24 pm
content: But I can move down/up and left/right

author: RAPo
author_rank: Super Contributor
timestamp: August 05, 2023, 07:45:31 am
content: That's a bummer. Could you post a photo with the settings where you cannot trigger?If you set the test signal back to channel I does it show the two lines?If so press the dual button, set coupling of channel II to gnd do you see three lines (maybe after positioning chII up/down)?I meant not only the voltage, but is the transistor working? (0.76 is not a bad value).

author: skopg
author_rank: Contributor
timestamp: August 05, 2023, 08:21:29 am
content: Hello, I'm looking, for the transistor I just know how to measure but I don't know how to trigger it (what you asked me).You ask me to press the double button...which...

author: RAPo
author_rank: Super Contributor
timestamp: August 05, 2023, 08:30:17 am
content: For now, please don't focus on the transistor. We are in the process of discovering what works and what does not. After that, we get to the stage of looking at components for the culprit.We had significant progress by just fiddling with the knobs. It would be great if we could return to a state where channel I displayed the correct info.

author: skopg
author_rank: Contributor
timestamp: August 05, 2023, 08:39:54 am
content: There it's done

author: RAPo
author_rank: Super Contributor
timestamp: August 05, 2023, 09:05:12 am
content: Thanks. I see that some knobs have changed.Please turn hold off completely clockwise to a minimum.Set the delay knob to 0.1usSet the knobs with the white arrow completely to the right in the detent position.Set time base to 0.2/divMove the channel II trace up so it is in the middle of the CRT.Next, set coupling ch I to AC, set coupling Ch II to GNDSet both CHI and II to 0.1V/divSet the CHI/II button into a depressed state.Press the dual button in and apply the test signal 2V to channel I, there should be 3 lines on the screen and the Trig LED should be lit.The middle line should be moveable by the Y-pos II knob.Do you see them?If so, reverse the role of channel I and IIKeep the dual button pressed in.Set Ch I to GND coupling, CH II to AC coupling.Press the CHI/II button in (this ensures triggering will be on channel II)Apply the test signal to CH IIAgain the three lines should appear on the CRT.In this case the middle line should be moveable by the Y-pos CHI knob.

author: skopg
author_rank: Contributor
timestamp: August 05, 2023, 10:25:14 am
content: There it's done

author: skopg
author_rank: Contributor
timestamp: August 05, 2023, 10:27:42 am
content: suite

author: RAPo
author_rank: Super Contributor
timestamp: August 05, 2023, 10:41:57 am
content: It is not very easy to see, but did you press the chanI/II Trig I/II button in the last photo (canal2sonde.jpg)?If you do, I'll bet the triggering led comes on and as far as I can see your scope is working fine.

author: skopg
author_rank: Contributor
timestamp: August 05, 2023, 11:54:33 am
content: yes I did it

author: RAPo
author_rank: Super Contributor
timestamp: August 05, 2023, 12:02:58 pm
content: Great! Do you need further assistance?

author: skopg
author_rank: Contributor
timestamp: August 07, 2023, 10:20:26 am
content: Hello, here is as requested, with ChI/II and Trigger pressed.But the Trigger lamp not on

author: skopg
author_rank: Contributor
timestamp: August 07, 2023, 01:06:20 pm
content: Hello, here is as requested, with ChI/II and Trigger pressed.But the Trigger lamp not on

author: skopg
author_rank: Contributor
timestamp: August 07, 2023, 01:42:37 pm
content: Hello, already a big thank you for your help.Is it normal when I press the button Ch1 the trace moves down (a Square).If I do the same for the Ch2 the trace also moves a square BUT upwards.Button or it is written invert/CH1 and invert/CH2.

author: RAPo
author_rank: Super Contributor
timestamp: August 07, 2023, 01:46:06 pm
content: Does the trigger led turn on if the level knob is wholly turned ccw detent in AT(=automatic triggering) position?(see pag 15 in the manual)/

author: skopg
author_rank: Contributor
timestamp: August 07, 2023, 02:18:08 pm
content: No and the Level button is on AT, on page 15 I only see testing diodes, semiconductors ...

author: RAPo
author_rank: Super Contributor
timestamp: August 07, 2023, 02:55:06 pm
content: Regarding your earlier question:QuoteYes, that is normal.See the attached image for the pages regarding triggering.Please set the holdoff to minimal.If you slowly turn the level knob from fully ccw AT position (with CHI/II depressed and signal on CHII) does the signal trigger somewhere?

author: skopg
author_rank: Contributor
timestamp: August 07, 2023, 04:08:46 pm
content: suite

author: skopg
author_rank: Contributor
timestamp: August 07, 2023, 04:10:08 pm
content: Suite

author: skopg
author_rank: Contributor
timestamp: August 07, 2023, 04:14:11 pm
content: Suite,Sur le TekCanal1 Time/Div 0.2 msVolts/Div 1Canal2 Time/Div 0.2 msVolts/Div 1Reporté sur le Hameg

author: skopg
author_rank: Contributor
timestamp: August 07, 2023, 05:04:40 pm
content: That's it, set to AT, the signal goes from left to right,released level button turn slowly to fix the signal you can see that the trigger lamp is on.