开云体育

Thanks Alek. Another friend mentioned a tube tester. I have one but it's put away and hasn't been powered up for about 7 years. I'll have to see if it'll test them. 73 Bob W4JFA [email protected]>

It is very simple to check. Use a 1kV Megger or even a 500V one and measure between grid and filament and I bet it will show big conduction. You will also see the blue glow deep inside and the

Lou, No intention on using it again. It would be good to be able to diagnose for the future. Since it blew the fuse immediately it didn't appear to be a heat issue to me but the explanation above

9 times outta 10 you won’t find a shorted tube ohming ?it with a meter. ?If you catch a tube short with a meter it’s because the grid is obliterated and debris is all over. ?Once Chinese tubes

If the tube is loose and rolling around, you can get / make / borrow a 6.3V supply and hook up the filament with clip leads. You don't need a socket, and you especially don't need the amp that the

Another piece of ham lore is -- if you run the heater for a day, the getter will get hot and absorb the gas. That's worth a try, and won't set your backyard or basement on fire. 73 Jim N6OTQ

That's prolly the answer. I put my friends amp back together so I cannot test it now plus it obviously puts stress on everything so I'll mark it bad and test it at a later date. Your theory makes

The tube is likely gassy and will only conduct when HV is applied. It usually takes a few hundred volts for a gassy tube to conduct so the low voltage from a test meter will not reveal a gassy tube.

Rich Measures (SK) wrote about this, and suggested (for different tubes) a possible way to fix it by swinging a live tube around your head. I guess if you do it outdoors and the tube is already

Jim, Can you point us to a good filter material to use? Maybe a link? Jim – KR9U Sent: Friday, September 8, 2023 1:13 AM To: [email protected] Subject: Re: [ham-amplifiers] Operating RTTY FSK

Hi all, I'll condense this, you'lll get the idea. A friend has an 811H with 3 year old 572B's. One shorted and causes the fuse to blow immediately. Tube replaced and all is well. Measuring with a DVOM

This is exactly why you install or retrofit a filter on the air intake. https://www.arraysolutions.com/amplifiers-rf?product_id=14890 On a side note, a shop vac on the bottom of the tube will get most

Gents, {S N I P} ... make sure you check the tubes occasionally for a buildup of dust in the cooling fins. Don't simply look at the bottom of the tubes, but pull them out and look through them at a

Of those two specs, the GRID current is the most critical. Protect against high grid current at all costs. 73/jeff/ac0c alpha-charlie-zero-charlie www.ac0c.com

One other thing Ron, make sure you check the tubes occasionally for a buildup of dust in the cooling fins. Don't simply look at the bottom of the tubes, but pull them out and look through them at a

On your tetrode, you are matching 50 ohms to? 1000 ohms (now 500 ohms), so the PI net values are all different........ vs? the 50 ohms to 50 ohms on the 3x6 (and 3x3). When matching to 500 ohms, the

Morning Jim Got it. Thank you Ron KK7GO Get Outlook for iOS<https://aka.ms/o0ukef> ________________________________ Sent: Monday, September 4, 2023 8:32:01 PM To: [email protected]

The muffin fan on the back is the optional fan. The optional fan adds to the air flow through the tubes and a lot of air movement around the transformer. Jim - KR9U From: [email protected]

Dear Jim, (et al), Nice to see a good suggestion about running RTTY through an amplifier, e.g., TubeMax. I run an Alpha 76A with a coupla 3CPX800A7's with an outboard supply, and the W7RY triode board

Thanks for your reply. My 86 has the blower and a fan on the rear panel. Is there another fan that can be installed? The blower does have ducting to the tubes. Ron - KK7GO Get Outlook for