yahoo.com@groups.io> wrote: It's the first relay on A11/A12 that either shorts across or puts the input coupling cap in-line with the signal. See the capacitor that's the first thing after the input?

http://www.condoraudio.com/wp-content/uploads/Projects/Tektronix-2465B-Oscilloscope-Restoration-Repair.pdf

G'day Graham, A fellow Aussie here, replying to your post. A quick message to let you know that I can help with your 2465 picking up that bad habit :-) Given your explanation, it is most likely that

https://scontent.fskg1-2.fna.fbcdn.net/v/t1.0-9/97187201_10219673347937322_395171359560302592_o.jpg?_nc_cat=100&_nc_sid=8024bb&_nc_eui2=AeFcV3iGeHAhlLW-i8_1fpTH-QaHFKCSjs_5BocUoJKOz6liUk6sEdjHyw8Y2lW9

I as looking at schematic 4 which has the inputs and I don't see (noob?) the part that makes the distinction between ac coupling and dc coupling... I see the signal go from the relays and the dividers

Brasso IS quite abrasive, has Kaolin and crystalline silica in it. See: <https://mbyc.net/MSDS/Brasso-Polish-MSDS.pdf>    There are a number of contact cleaners n the market, such as Caig Deoxit

Thanks guys! I will check it out!

Cleaning those switches (and all types of copper or other contacts), is done perfectly with Brasso. NEVER use any abrasive material on any contact surfaces on any equipment.

At this point, it would be good to narrow down just where the CPU is getting stuck. The fact that you have all lights on means that the CPU has started self-tests, but it never finishes. So, let's

You can change the file extension from .dd to .img on a Windows 10 machine and then mount it as a virtual drive or burn it to CD. Probably works on Windows 7 or 8, too. You can also mount a .dd file

Essentially, Chuck's post explained a bit about why the lack of HV was causing Q552 in mine to overheat. If your F558 is okay, then that may not be the problem in yours. As for running it with the

I can't find that post, let me ask you. My all other voltages are OK, like I mentioned in my previous post I have -5V, +5V, +32V and even +51.6V on C558 only missing voltage is +95V All fuses are OK

Hi Stephen, Thank you so much for responding There are 3 knobs on the TDS420A that are the larger size (~=19mm) for Vertical Scale, Horizontal Time Base and the General Purpose knob. There are 3

/facepalm/ I read 'ALT' as 'All.' Okie, so back to the ROM board, it would seem! I might just delete this post. thanks Dan!

I meant ADG281.... sorry, I wish I could help but I will be eager to know how you will proceed

Hi Paul, Normally, a failure of the display subsystem self-test should result in all vertical and only ALT horizontal mode switches being illuminated. If you are really seeing all mode lamps lit,

so basically you are saying that channel 4 has fallen into channel 3 and is controlled by ch3 both in position and gain? and ch4 position/gain controls have no effect? is that right? strange indeed,

I'm not sure I can answer that. Looking back in my emails, when I pulled Q552, it did not check correctly. If I recall the sequence of events, L582 was open (broken wire). When I replaced that, the

Hello, I recently acquired a TDS3034B which was initially "brain dead" - LCD backlight would turn on, but nothing else would happen. Thanks to information found on the EEVBLOG forum, I was able to

Hi all, I am currently working on repairing a Tek 475 scope which I bought around 2 years ago for a bargain, which isn't sweeping and appears to be stuck in hold-off. I've tried best to summarise the