- Hameg hm205 3 service manual manuals#
- Hameg hm205 3 service manual manual#
- Hameg hm205 3 service manual full#
You must get yourself a copy of the manual as well, and study it carefully. If all the voltage rails from the power supply are about right (+-10% at this stage is adequate), then you will have to start to analyse the operation of each function in detail: Y amplifer, TimeBase, X Amplifier, CRT power supply, CRT blanking (Z Amplifier).
Keep away from the EHT supplies to the CRT.īut much of this is dangerous unless you really know what you are doing, and are used to working with live mains equipment. I would start, working in order, with check mains plug fuses, check voltage into the mains transformer, check voltages out of the transformer, check voltages on each of the power rails and the 120v power rail fuse. I am afraid I cannot really help you much, as the Cossor 4100 oscilloscope is a very complex machine, and your question suggests you are not at all used to electronic equipment. Note that Emitter of Tr100 &Tr101 is very low impedance, so no voltage swing will be apparent.
Follow that back to the input, from TB, pin6, and Brill pot p15. This will also vary with the brilliance control. There will be a swing of about 50v+ at the output of the Z Amp, collectors of Tr105/106 between the two states.
Hameg hm205 3 service manual full#
Then repeat with full brightup - ie on external X setting as for X-Y plotting.Ĭompare and see what changes. Do this with no brightup - ie no Timebase, no sweep. Abbreviated way of saying: Note the voltages on the emitter, base and collector of each of the transistors Tr100 to Tr106, and write them down in order. I think you will find the Circuit description section helpful, and you will see the reference to a Brightup Circuit on Fig 3.1c. The Blanking Amplifier or Bright up Circuit are the usual terms for the Z Amplifier, Fig 5.5/2. Telequipment and Marconi are both reasonable. (Go for Tektronix, Hewlett Packard, or Solartron.
Hameg hm205 3 service manual manuals#
Good luck, as Cossor manuals are not the easiest to learn from. These instruments are fairly sophisticated, so you have a nice challenging learning task. Incidentally, my copy has a list of contents and circuit description in section 3, which provides in effect an index. The Set Brilliance control R219 on Fig5.3/2 may be out, but I would worry too much about that until you have checked as my first para upon the existence of a Brightup pulse. If you look at the EHT supply, fig5.3/2, you will see the grid supply windings on T200 (h,i) are floating, and the bottom end is fed from the Blanking Amplifier.
If that is solved, then the end of the sweep disappears. Taking Nigel Goodwin's point about actual method of brightening the tube, on high speed scopes like this, the brightup pulse has to be DC coupled in some way, as otherwise the sweep has almost finished before the coupling capacitor has charged up enough. You didn't say whether the brilliance is uncontrollable, or turned up very high both indicative of Blanking troubles. But you do really need another scope (almost any will do) to check that a bight up pulse comes into the Blanking Amp from the TimeBase (pin6 T/B Z) and that the Brilliance control also works. Usually one of the two high voltage transistors will have failed. Look at the CRT Blanking circuit (I am quoting references from issue 2, 1973):Z Amplifier, PCB5, circuit fig 5.5/2. Hold-off alters the time after the end of a trace before it can be re-triggered, and so usually you will get a slower retrace on the screen. If you get more of the shaddowy trace, then that suggests my guess is right. Confirm this by getting the same trace as your picture, and then alter the "hold-off" control. In French: TSF for Télégraphie sans fil.Īll listed radios etc.Looking at your picture, I suspect the retrace blanking is not working properly. Here you find 113 models, 106 with images and 93 with schematics for wireless sets etc. See "Data change" for further contributors. Abtastrate 2 × 20 MHz, Speicher 2 × 2048 × 8 bit, Zeitbasis 5 s-1 µs/cm, DotJoiner. 1 mV/cm, Komp.-Tester, Zeitbasis 1 s-20 ns/cm, Triggerung 0-40 MHz. Model: Oscilloscope HM205-3 - HAMEG GmbH, Frankfurt.Alternating Current supply (AC) / 110-240 Volt.
0 kommentar(er)
