Need a good recomendation on a Biasmeter to bias my JCM 800 2205 and Fender twin reverb amps

[DrGonz78]

Get something like this and then later fix the other one. Heck yeah.

https://www.ebay.com/itm/12433456471...Cclp%3A2332490

[g1]

which ones should i purchase and where?

Did you see post #9 ? Those are the parts you need.
Beyond that, how can we tell you to fix it? You remove the broken and install the new.
Same type parts also available here:
https://hoffmanamps.com/MyStore/catalog/parts9.htm

[mozz]

Beware on those ebay ones. I have a dual version and when you click to socket 1, it lifts the cathode on socket 2. Will post picture after work today.

[Tom Phillips]

Beware on those ebay ones. I have a dual version and when you click to socket 1, it lifts the cathode on socket 2. Will post picture after work today.

Wow. Makes one wonder what else lurks inside those non-certified kits of test gear and how accurate the ones are that incorporate built in current/voltage displays.

Personally, I have always used my existing bench gear to set bias. I don't mind pulling the chassis to do so and I think it's good to take a look at the guts when it's time to set the bias. A long time ago, when I considered using a dedicated bias meter, one big con was that there is not room in some cabinets to install the bias meter socket and the tube without removing the chassis from the cab anyway. There would also be the need for addition adapters for oddball tubes and EL-84 types.

[DrGonz78]

Beware on those ebay ones. I have a dual version and when you click to socket 1, it lifts the cathode on socket 2. Will post picture after work today.

I never tried those. Actually I dropped that in there for a reaction. I almost asked if anyone tried these things. Thanks for looking out. More curious than serious.

[mozz]

I guess the way it's wired there's a 1 ohm resistor for the meter. The switch chooses between the tubes and lifts the unused one. I noticed the current change because i have a homemade socket with test points i used before buying this. I ripped out the switch so i use it as a single. Sockets plug in with a 1/8" mono plug, i have made up 6gk6, 6bg6, 6ar6 and other oddball tubes i use for outputs, factorys were el84 and 6v6 type sockets.

[Tom Phillips]

I guess the way it's wired there's a 1 ohm resistor for the meter. The switch chooses between the tubes and lifts the unused one...

I was assuming that "feature" was a wiring mistake. If it was an intentional part of the design, then it's a really bad product.

[Grrrg]

Man, i posted some pics and ask for replacement parts. which ones should i purchase and where? Do you need better pictures so you can advise me properly?

Dude, if you want people to help you, politeness is not the worst to start with. And nobody can help you step by step. Basic knowledge and skills are required.
I use a DMM for setting bias.

[Chuck H]

Dude, if you want people to help you, politeness is not the worst to start with. And nobody can help you step by step. Basic knowledge and skills are required.
I use a DMM for setting bias.

A lot of people treat any internet resource as benign reference. Ignoring or not caring that there are actual humans involved.

In this case the necessary information about parts and process WAS given. Since Jquijano still wasn't clear it was handled the way you might read Ikea instructions that confused you. Indeed a better approach would have been to say "I'm still not clear on this." Some people just need the world to be responsible for their shortcomings if they are to live with themselves. So other people get little more regard than a banana, a lamp or a toaster oven.

[mozz]

I think there may have been a language barrier in there.Maybe once A.I. takes over, there won't be any feelings to get hurt, until they get pissed and do a coordinated attack on you.

[g1]

Yes, I was also assuming there are some language barriers or perhaps translators in use.

[Jquijano]

Did these ever work properly while in your care? If no, go find the smedly that sold them to you and work them over good. If yes,.. Why did you jack them up like that?

Well i guess ill use it as it is with only the two terminals working. I do know how to solder to terminals, test continuity measure voltage, etc. What i dont know is how these guys in Weber built these lousy probe terminals?

[DrGonz78]

Well it’s not something I have made before but it seems rather straightforward. You are really asking how to get socket apart or something. It’s probably glued together. I sometimes have used a hot torch to heat a razor blade to open up wall warts. Actually this thread got me thinking I should make up a few of these to learn how.

As an example here is a diy socket. Perhaps you could build something that would work on your tester. Maybe figure out how to open up the probe socket and see if it’s fixable.

https://el34world.com/charts/BiasChecker2.htm

[Helmholtz]

As an example here is a diy socket. Perhaps you could build something that would work on your tester. Maybe figure out how to open up the probe socket and see if it’s fixable.
https://el34world.com/charts/BiasChecker2.htm

Unfortunately the link describes building a socket adapter which breaks the cathode to ground connection unless an ammeter is connected.
While this works, I much prefer the type where an 1R resistor is inserted between cathode and ground, which keeps the tube in-circuit regardless if a mV-meter is connected or not.

[Chuck H]

Well i guess ill use it as it is with only the two terminals working. I do know how to solder to terminals, test continuity measure voltage, etc. What i dont know is how these guys in Weber built these lousy probe terminals?

I suppose it's possible Weber used an adhesive that wasn't as heat stable as it should have been? But the socket parts would be the same stuff we all get so there's no faulting the quality of those. And as a company Weber doesn't get much grief for being poorly made products.

To be honest I don't like the design anyway. The units are so tall that you need to pull the chassis to use them for many amps. And once you have a chassis pulled there are other ways to check bias that don't require a plug in socket. It seems practical to the point of being obvious that such units ahould be as short as possible.