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465B Attenuators
I recently rewatched Zenwizard YouTube video about his 465B calibration. He mentioned the nightmare the attenuators were. Well, I¡¯ve been pretty much experiencing the same thing with mine. Whatever
By Stephen · #190935 ·
Locked Re: Dennis Tillman
Right. Chuck was instrumental in helping me fix my 7904. We need him! Why was he banned? John Justin
By JJ · #190934 ·
Re: 7A19 Fuse (later model, on attenuator - thin film?)
I would have thought that a fine wire would have too much inductance unless it were extremely short and then you have the issue the heat conducted to the mounting posts will increase the current that
By Roger Evans · #190933 ·
Locked Re: Dennis Tillman
I second that.? Chuck is a great resource.? ? ? ? ? ?Jim Ford?Sent from my T-Mobile 4G LTE Device
By Jim Ford · #190932 ·
Locked Re: Dennis Tillman
The group owner is not Dennis and it was the group owner (Michael Dunn) that banned Chuck. Both Dennis and I are moderators and we could theoretically remove the ban, but that would be stamping on
By David C. Partridge · #190930 ·
Re: 2445 Power supply Fail
Ran the scope up with variac , slowly a couple of times , a/c to pcb board after mains switch voltage on DC out from bridge 309 volts DC. a/c in 250 mA stable. power on/off at full voltage , nothing
By Graham · #190929 ·
Re: 5403/D40 Scope with no trace
Ok my new capacitors have arrived. However, I have no idea how to disassemble the power supply. Is there at least a good trick for removing the can capacitors without lifting all the traces? Thanks
By info@... · #190927 ·
Locked Re: Dennis Tillman
I agree that Chuck should be reinstated if we wants. DaveD
By Dave Daniel · #190926 ·
Locked Re: Dennis Tillman
I can't wait until Dennis is back so Chuck Harris can be reinstated. larry
By Lawrance A. Schneider · #190925 ·
Re: 7904 problems
Hi, yes I agree. I had a similar 7904 problem years ago. In tic mode there was also a hissing sound. The problem was the HV multiplier. G?ran
By G?ran Krusell · #190924 ·
Re: 7904 problems
A minimum load is indeed required, in the order of 50 W. The cause of tick mode might also be in the HT wiring. In an old message #64991 I wrote the following: "My 7904 stayed in tick mode because of
By Albert Otten · #190923 ·
Re: 7904 problems
Hi all, I'm battling away with the two 7904s. The one with the faulty CRT had a functional power supply. The other one was completely dead despite having intact fuses. I transplanted the working power
By Morris Odell · #190922 ·
Re: 7A19 Fuse (later model, on attenuator - thin film?)
Hi,? I looked in 7a19 and 7a24 manuals and fuse listed for f100 (7a24) and f10 (7a19) are the same with part # 159-0118-00, which doesn't agree with your number.? Both plug-ins have 2 spare.? I
By Carl Hallberg · #190921 ·
Re: 7A19 Fuse (later model, on attenuator - thin film?)
The Mouser surface mount fuse idea has merit, Harvey. I would solder it on the lower ceramic substrate, bridging the blown thin film. It would still need to meet the 0.3 ohms (or less) spec. to keep
By Cliff Carrie · #190920 ·
Re: 7A19 Fuse (later model, on attenuator - thin film?)
I think I may have answered my own question. A glass fuse rated at 0.2A and 1 1/4" long has a resistance of about 6.75 ohms. To get down to 0.3 ohms using the 0.2A rated wire from such a fuse would
By Cliff Carrie · #190919 ·
Re: 7A19 Fuse (later model, on attenuator - thin film?)
Hmm, I haven't tried at all. you might be able to do the following: 1) design a PC board with the fuse shape.? Be sure you panelize it when you send it off, you'll get lots for very little. The fuse
By Harvey White · #190918 ·
Re: 7A19 Fuse (later model, on attenuator - thin film?)
Has anyone tried to open and repair one of these ceramic-based stripline fuses?? This thread has been dormant for some time. A 0.3 ohm fuse resistance makes sense in a 50 ohm terminated input. It
By Cliff Carrie · #190917 ·
Re: Troubleshooting 465Bs With Dead Channel 2
Tom, See if CR1796 is bad (shorted). Clean the pins and sockets for the transistors and IC. The pots may need cleaning as well. It is possible a transistor is bad. See about the voltages at points
By Mark Vincent · #190916 ·
Re: Probe tips P6133 and P6137
Hi all, thanks for the information provided. I decided to modify the P6133 probes into 1x probes: I opened both the broken probe tips, and replaced the burned hybrid with a zero Ohm replacement. I
By satbeginner · #190915 ·
Re: 2712 Spectrum Analyser, manual VR RBW filter level DAC setting on A13.
Hi Jaap, Did you manage to get information on converting a 2715 to 2712? I have a 2715 and tried to change the resistors on the motherboard and now it says "Misconfigured Spectrum Analyser" on the
By arainhoneves · #190914 ·