So one electrical line (neutral or phase depending on the connection to the socket) is connected to the metal chassis of the electronics. Moreover on this TSF not only the high voltage (350V peak) is present, but it is equipped with an autotransformer. Indeed, it is necessary to take great precautions for oneself (risk of electrocution by propagation of the HT by the mass to the Hantek metal case) and for the equipment (HT input on Hantek6022BE, and PC) during interventions. Thus equipped, I will be able to measure the frequencies present in the different stages. I immediately tested the set: the Hantek6022BE card, the probe x100, and especially your software, that i now know how to use thanks to your message of yesterday. So I bought a probe x100 (9,59 € shipping price included by internet out of the forum, if you want i could give you the address), and I received it yesterday. By dint of research, I discovered the card Hantek6022BE which has just the necessary characteristics, except as regards the input voltage. The only way to find out is to use an oscilloscope. But first size difficulty encountered: I located the fault upstream of the frequency change stage, but I'm not sure. So I set myself a real challenge: repair it, and offer it repaired for his birthday. I recently discovered that my son-in-law who works for an ISP is very interested in old radios, but he does not have one, and does not know about my treasure. Hi Martin, This TSF comes from my family. (This limitation is found in most scopes, even in the most expensive ones.) Have fun Martin So _never_ connect the probe's GND clamps to any other level than the GND level of your radio. Another thing to remember to avoid damage to your computer and scope is that the scope's GND signal is directly connected to your computer and via the computer's power supply a connection to the earth potential of the mains exist. With the open end of this capacitor you can touch the interesting points in your radio, wait 'til the trace (that has jumped to the top) comes to the center again and stabilizes and then measure the AC while the capacitor blocks the DC offset (it charges itself to the DC voltage within seconds, so you should discharge it (easily done by touching the metal frame of the radio with the open end for some seconds) before measuring at different levels or touching by hand to avoid the painful (but not lethal) electrical shock. Another possibility for measuring smaller signals with a high DC bias (as usually found at the anode of the nice dusty tube on the left in your 2nd picture) is to create an AC coupling (that's unfortunately missing in the Hantek in order to spare some ct in production) by connecting a small (~10.100 nF) plastic film capacitor in series to the tip of your probe, this capacitor should have an operating voltage > 500 V to be on the safe side. For higher voltages a X100 probe can be used but these are expensive. Supplied with the scope are two probes that can be set to X1 or X10 mode, the later setting allows to measure ± 50 V signals (with ☓50 V safety margin). The input (at the BNC plug) shall never exceed ± 35 Volt to avoid degradation or damage. I started my electronic experiments many years ago with gear like this - been there, done that Just out of curiosity - what kind of measurement tools do you have at hand when working with tube radios? Regarding the Hantek scope, please keep in mind that the usable input voltage of Hantek6022 is limited to ± 5 Volt (voltages outside this range are clipped and the channel name in the bottom lines turns red as a warning (as seen in my screen shot some posts up). Hi Raxis13, Nice historical radio, but due to high internal voltages also a bit dangerous.
0 Comments
Leave a Reply. |
Details
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |