I worked for ETO from 1984 to 1989. Started as an assemblers on the MRI line, then in the lab tuning the MRI amplifiers, then went to the alpha lab doing startups on new amps and serviced old ones. Then production supervisor for a time. Just got my ham general license April of 2021. Thank you so much for this video. Brought back many good memories and chocked me up some.
Always love the videos. Big fan of yours. My question is you are using a7300 to key the amp. I have been reading that that rig hard keys the relays in the amps and can damage the amp or the radio. I found some info on QRZ and they are calling it overshoot. I have a Alpha 8410 and would love to use my 7300 but don’t want to damage it. Just want to get your thoughts. Thanks for the great video. I know that you can set the delay on the 7300 to key the amp but they still say the overshoot problem is still there.
How long to ramp up on variac? (1 minute, 5 minutes, in steps or slow turn dial?) Also, in order to heat tubes like you did, simply disconnect the leads on top of tubes? Don't need to transmit during the "cook" time, and just in standby mode? Thank you in advance!
I was basically given one of these back in the late '80s. As it had no transformer, I had no way to test it. A friend had a usable transformer so I sent it home with him. He got it working (something like 900w due to a smallish transformer) so he wanted to buy it. Sold it for $300.
These amps were the best of the 1990s. ETO would set up their display at Dayton, put a brick on the key, and have it run for the duration of the hamfest.
After seeing that done at Dayton, I started doing the same thing on a lot of amps I repaired that I knew could handle it. I would get some very strange looks from customers when I would put a weight on the key, a big fan on the dummy load, and suggest that we take a ride to the truck stop for some coffee and conversation....
I own the predecessor of the 76a an Alpha 374a. Most of the pics you find online are my Alpha. I uploaded them to Alpha years ago. Mine is the 374a on the white desk. The 374a doesn't have the robust hv transformer as in the 76a. My 374a has 3 good full output 8874's. It was designed to do legal limit in its day. The legal limit back then was different than it is now. Lower. What is your opinion of the 374a? Have you ever had chance to evaluate one? I agree with you that Alpha amps are works of art. Oil filled hv cap. No expense was spared. I bought my 374a over 30 years ago for $1000 out of an estate. It has served me well. I am rebuilding my Heath kit SB-220. Your SB-220 video's are very informative. I read elsewhere to ground the grids like you do and remove the chokes. One of my chokes were burned. My SB 220 was given to me as a box of parts. Thank you so much for the review and your tips. I wish I knew a fraction of what you know. I'm having fun watching your video's. I'm trying to learn more about rf amplifier design. Your video's are very good. You are a good teacher.
Wow nice I have a 78 and a 87A , funny that you don't know who Dick is , and yes he is a legend and a gentleman Cheers from Canada P.S. was hoping for the last three years of you working on my Monster Henry but shipping charges have made it unjustified, I know about shipping I'm in it thanks again love your vids. Home of the Freedom Convoy,🇨🇦🇨🇦🇨🇦
Hey Mr. BBI, I got a plate transformer that's got rust only on the bottom but I'm not sure if I should sand it down and leave it be or sand it and use a paint coat to prevent more rust. I plan to make a PS but it weighs 40lbs and aluminum won't hold up so I need to use steel but then of course it rusts. Any other ideas that keep it grounded and rustless or would it not matter because I shouldn't touch the thing anyway?
Peter Dahl got purchased. They primarily bought the company so that they could get the commercial side of the Transformer business. The only company left that will build you a transformer in the United States that doesn't have their components manufactured overseas is electronic product design Peter egerman. If you have a Transformer that has gone bad you can send it to him as long as you know what the primary and secondary windings were he can manufacture two that spec.
@@spaceflight1019 looks like BBI's right, I only see used PD stuff on eBay, etc. Can't find anything on Peter Egerman though unless that was a typo. But regardless of that, they look to have great quality.
I have the Alpha 78 with 8874 tubes(3) I'm scared to turn it on now cause it has been sitting for 7 years. It runs 220v which I have. I want to sale it I guess & its worth a lot more in good working order. It had newer tubes as well. Thing weighs a freaking ton, I can't move it by myself anymore. 😥
Buddy of mine had his Alpha 78 sit for over 15 years. Before turning it on, he sent it to Dick Byrd (N4UQ) to go through it and upgrade everything, including WARC band upgrade and changing the RF input RCA plug to an SO-239. Amp came back with a new tuning specs and the thing is a rock. If the tubes are still good, it's a keeper.
