Fender Deville 212 Repair - Screen Grid Resistors 

Thanks to a couple viewers pointing out an error on my behalf, I should have replaced the 1 watt resistor with a matching 1 watt resistor. If anyone is following along with similar repair, please take note. Thanks! :)

I do amp repair myself. I like watching amp repair tech videos. I am always trying to expand my knowledge and skill sets. Your video is one of the best. Clear and concise 👍

To remove the valve base pcb, remove the valves and undo the screws from the underside. The visible screws on top only hold the pcb to the stand offs. Once unscrewed from the underside it will just lift out with the stand offs still attached.

I see your calculations on the bias voltage, however..... The documentation says to set that voltage at 60mv. (giving an average of 30mv for each tube. ) I have an amp with this problem, got parts on order! Great video thanks for taking the time to do it! I especially appreciate the guitar playing showing off the amp with the problem, then an after video! That really helps!!

Hey brother. I've never watched Amp repairs before. I have a California 2×12. Deville 1997 model. I was intreaged bye the bias settings. You do a fine job with your teaching. No bullshit. Refreshing. Thank you my friend. A whole bunch. 😊

I as well own a DeVille 2x12, a 1996 40th anniversary with the golden hologram sticker. It blew after 4 years of service and sat with it's cover for many many years until I convinced my brother to sell it to me so I could have it repaired. It had some surgery, the usual for Deluxe's and DeVille's. I bought some Jensen Falcons to replace the stock speakers and it sounds good. I previously bought a pair of Jensen/MOD's for my B-52 100 watt 2x12 that absolutely rule ! I should have bought another pair for my DeVille but I did not! MOD equipment and electrical components are solid!

Holy Cow! You are good! Just picked up a 2004, 40 watt, 1 X 12 version, local pickup, for 300! I knew from the seller description the Power/ filter caps were old. Put a whole new set of F + T 500V 47 uf's, The Drive channe'l works, don't like the drive sound, but the clean channel sounds unbelievable! Bass Mid and treble on 5 is so good already, and I can't even put the volume past 3, It's soooo loud! No break up whatsoever. Also have 2 , 10 inch Peavy square backs, external cab, Sounds waaaay better that the stock 12 that came with it. Thanks for the inspiration!

To get those back screws out in the past I've taken a Phillips bit and put in at a 90° angle in a small vice grip and just unscrewed them took awhile but it was a lot faster and easier than taking all that other stuff out. I'm sure there are better tools than a bit and vice grips but it's what I had on hand. And of course this is after fully discharging the caps since you're going in there with an un isolated metal tool.

This is one hell of a instructional video, outstanding job...

I’m not saying my way is best. But to drain the capacitors I unplug, turn the amp on, and play my guitar for 30 seconds. Then I verify they are drained with my DVOM.

Finally, a great amp repair video! Great detail and informative. Thank you!

Thank you for the video, I am trying to learn more about amps

Excellent, detailed procedure. Thanks for sharing.

This is EXTREMELY informative. Thank you!

very nice ! shared knowledge is blessed by God! thanks for this video! you play a lot!!

This was one best vids I’ve seen

Usually screen grid resistors are underrated. Many amplifier manufacturers, put low wattage resistors in that place and it's the best way to blow the power tubes as well when they fail. Moreover, I'm not a big fan of amplifiers with octal sockets soldered directly to a PCB. It's a big mess to troubleshoot that kind of an amp. I hate solder suckers!

Awesome man.

I had a more or less identical issue with a Groove Tubes 6L6CHP just like these not long ago as well. Had an internal short in one and it ended up taking out a screen grid resistor. Kinda sucks that those tubes weren’t very reliable because they actually sounded pretty nice!

I know it's been a while since this was premiered, but I have to say - the 1W screen grid resistors are better than the 2W resistors because they are supposed to act as fuses to protect more expensive components such as the power transformer in the case of an internal tube short. The screen grids are insurance for shorted tubes, and are far more affordable than transformers. As designed the 1W resistors are not stressed in normal circumstances. But if there is an internal short then hell yes, let that resistor blow.

The OL usually stands for Open Line

I really enjoyed this video. Just wondering if you have ever worked on the Fender Hot Rod Deluxe. I have one right now that has a problem with the drive channel. It does not turn on at the front panel. When I use the foot switch, the pedal lights up correctly but the drive channel still does not come on. Any help would be appreciated.

Exact repair im needing to do on my Deville iii 212 except my resistor doesn't look fried, its the attachment solder points at each end that look cooked. It cooked all the solder off the points. This shouldn't be any more or less an issue during replacement will it? I'm hoping not. Thanks for such an informative video for us greenies. Much appreciated more than you know.

Great VDO - Which name brand capacitor is best to replace the Illinois capacitors?

Hi Shawn, thank you for taking the time to post your repair videos on Fender amps. Was wondering if you could help me with my Fender DeVille 212. I have an issue where the amp crackles when I hit certain notes. I've attached a video that demonstrates it. I am the original owner (many years now) and mostly I play it in my basement music area (i.e. it is not a road warrior). I've been living with this problem for a while now. I did take that back off a while back and did not see anything obvious. I do have some electronics background, but not so much with common issues with tube, tube amps, etc. Is there something wrong with the circuit board? Or do you think it's just a tubes? I replaced the 3 preamp tubes but not the power tubes, but the problem remains. Any direction you can provide would be greatly appreciated. Thanks!!! ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-yNWgNUeG83E.html

You can discharge the amp simply by switching the "power off" and keeping the "standby on" for a minute or two, which opens the circuit and allows the stored power to exit the capacitors, NO NEED TO DO THIS COMPLICATED PROCEDURE, ESPECIALLY IF YOU'RE NOT AN EXPERIENCED ELECTRONICS MAN, he's shaking like a dog shitting peach pits, he already hit about 15 things other than the capacitors

I knew the issue right off ! It's a throw away Fender. Just put amp in a dumpster, and purchase a different manufacturer's brand !!

Every single one of these amps fails prematurely. Total garbage.

At one moment I hear advantage of the PCB amplifiers is in ease of repairability. Seriously? This are the worst amplifiers Fender ever made. Nightmare to repair because you have to unscrew million stuff and bend ribbon cables that are prone to breaking. Those filter caps are notoriously bad. Every high power resistor in those amplifiers is point of failure. Those big once do not die as much but develop cold soldering connection. Metal oxide resistors die or runaway changing value. PCB fails as well. Lines break and they glue away as well. Every tube amplifier will need the recap job eventually and this is not nice job in this amplifiers. They are simple not made to be maintained. At the other side any old Fender amplifier with eyelet board and dog house is made to be maintained easy and last for ever. All you need is to desolder part, stab new one in and done. No need to unscrew a thing. Wanna recap filter caps? Just take off the dog house and there you go, instant access. You can recap it in 20 minutes maximum. So saying this amplifier is easier to repair is............. Online calculator for tube biassing? Seriously? I do use different calculators like tone stack calculator or bypass calculator. Those save tons of time when you are designing your own schematic. If you are amp tech you have some sort of bias probes and a few multimeters. Or you lucky and have probes that have both current and voltage meter on them. If your probes show only current you hook up voltmeter to see the plate voltage value. All you need is to multiply two numbers. Plate voltage and cathode current. And math is simple as well. 6L6GC Maximum plate dissipation is 30 Watt. 70 percent of that is 21 Watt. Easy 3 Watt is 10 percent hence 30 percent is 9 Watt. So when you multiply numbers and get 18 Watt you move the bias pot and read again the numbers and multiply them. Adjust till you get close. I say 70 percent because you are measuring cathode current with probes and that is plate current plus few mA from screen current. So if you read for example 47mA it is more like 42 to 44mA of the actual plate current. So for example 47mA times 450 V is about your wanted 21Watt but actually it is 19 to 19,8Watt plate dissipation and that’s under 70 percent. 70 percent is just an number. You do not want like 40 percent but anything between 55 and 75 will be working. Lower values will extend life expectancy of the tubes though. Biassing fixed biased amplifier is