Fender Frontman 212R REALLY needs some help..... Let's fix this!
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- čas přidán 5. 02. 2021
- This amp had failed speakers, and failed output transistors. It needed lots of help, but it's fixable. Some silly head put the heat sink on WRONG, and it couldn't dissipate heat. All is well now.
- Věda a technologie
love the cuckoo clock in the back when ur talking about some jack hold not know what he was doing in there lol
I've got 2 of them in the lair... I like mechanical clocks.
Yes lol that was classic!
I have one of these. It is slightly older. Just says FM 212R on the front panel in block letters instead of the nice script Frontman. The speakers were both blown when I got it. Two of the power resistors had de-soldered from the board. I fixed that and replaced a bad disk cap near the fuse. Installed new speakers and it worked. It temporarily developed a problem where the volume would stair-step up to ear bleed level at about 6. I cleaned the pots and installed some Eminence speakers with a lot of power handling and the volume problem went away. The amp sounds pretty good for what it is.
Fender stuff is popular... but the QC on the PCB's is a bit questionable.
You would wonder how inexperienced supposed 'techs' let these things go..! Dangerous people out there. Glad you got hold of it, great fix. Nice amp also. Thanks once again for sharing your knowledge..Ed..UK..😊
I'm guessing the previous owner made that error. if I ever take something apart, photos or video before and during the disassembly help prevent mistakes.
instablaster
I wonder if adding a cooling fan would help as well?. It is out of warranty so no problem there.
Dirty input jack switching?
I have a 212R and it makes pops and "gunshots". I have changed out the Q9 and Q10 (transistors) and it got a little bit better but far from good, I am waiting for Q8 and Q13..hoping that will fix it. Otherwise i do not know what that could be..
I've seen the high wattage resistors in these become loose... that would do it for sure.
@@DeadKoby I re soldered them when I had it apart last time but I may order new ones. Not sure how to check them.
On these SS amps, the pots must be tight to the front of the chassis... loose bolts means noise. Second of all, get a wood chopstick, and tap/press on each component a bit, testing the integrity of the solder, and the component. You may find the noisy spot by tapping around with the amp at a medium volume.
@@DeadKoby That is so funny I found out that just 2 days ago, had to really tighten it to the chassis, because when I went to the "crazy" channel it went berserk. I'm still waiting for the components so I have it running unmounted (just laying on top of the cabinet) and the very first thing I did was the chopstick thing and found nothing unusual. When I tighten it up it almost went quiet but after a while from time to time it now only crackles, no popping gunshots, That is what I believe is the replaced transistors because before it was very loud, but now it is even tolerable.
Thanks for replying!
This amp should be DARN LOUD. Voltage on the output transistors should be a -45 and +45v. The schematic is easy to find online.
What causes the transformer to blow. I got no power and can’t find a replacement transformer
A dead short.... When the fuse does not blow. Thats how power transformers die. The schematic has the part numbers.
Hey there! Great job....
I have the same amp... And yesterday the channel that selects between clear and distortion dosnt work... Which means that the amp doenst have the distorion channel working at all..... Have any idea?
Are you swithcing it via a footswitch or the onboard button? Footswitch has a habit of cracked solder. Switches get dirt in them.
@@DeadKoby i switch it via the onboard button.... I tried the footswitch after also.. Didnt make any difference.... Any thoughts what could it be? Maybe the button itself?
@@gusdee2320 try cleaning the button. Those switch with an IC on the board... So it could be the IC or a supporting component.
@@DeadKoby thanks, i ll give it a shot
It does take “guts” sometimes to work on SS amps. I have a Champion 40 that the volume control doesn’t work right.It will raise the volume and stop functioning while the volume stays at the same level It will not change the amount of volume, up or down. I first thought the volume control was defective or bad solder joints, but I did an up close(lighted magnifier) and could not see any problems. I tested the volume pot and went from 0 to max resistance, like it should. I’m afraid it has to do with associated circuit but I have not found a schematic. It did this from day 1, well maybe day 30. Once it started it has not changed. Have any ideas about what might be the problem? If I were near you, I would bring it in and have you look at it. I’m not so......also if anyone that has one and is or had this problem, please let me know how you fixed it. I’m thinking about turning it into a single channel Deluxe Reverb. Love from NW Colorado. Thanxz
The first test I would do is measuring the suspect pot all through the sweep.
Hmm.. Check electrotonya for a schematic... I find so much good stuff there.
MY AMP HAS LASTED LONGER THAN MANY OTHERS. DESIGN FLAWS THAT are hurt by vibration and heat. I like this solid state amp because Ican set it and forget it. No sound fluctuations because of dirty electricity. Where are you located.?
Northern Ohio... Greater Cleveland area.
Hey can you please explain what you meant by putting a little bit of insulation on the jack to coil it out?
I used shrink-wrap and covered the tip grounding on 1 side
@@DeadKobythe wire or the lug?
Apologies for all of the questions..i just got one from a friend and want to solve the same issue without having to resort to thre 220k resistor mod by Q17 i think it is?
@@DeadKoby I re-watched your video again several times I just caught on to what you said as far as the switched Jack is concerned I've used them before so I know exactly exactly what you mean I'm going to take the groundings a grounding side and I'm going to sleep a little bit of shrink tubing on there and the hump should go away did I get that about right
On a cliff jack, there's a contact between the two rear pins when you take the cable out. Prevent it with shrink tube or electric tape.
Hi I have the same problem with the noise without it plugged in can you show or tell me again what you did to fix this problem cheers
I can't diagnose your amp on just a guess. This one needed power transistors.
@@DeadKoby I understand but you said in the video you had the hum or buzz before you plugged the jack plug in and when you did plug it in the hum went, you rectified this by doing something with the input jack sockets can you tell me what you did as I am having the same the problem.
Cheers
Gary
@@Theintruder100 This was awhile ago, but I believe I insulated one of the two jacks to NOT ground the tip when unplugged. I can't be 100% certain anymore.
@@DeadKoby ok I'll have a go at that many thanks
I have insulated the jack socket tip and that has sorted the hum/buzz out apart from when the amp is initially turned on but I can live with that.
Cheers again
I realize that this is an older video, and a good one I might add, but I have this same amp with the same hum when unplugged. Your referal to dirty input jack switching... I did not totally get what you ended up doing. My thinking was that you cleaned the contacts where the contacts lift when a jack is inserted but wanted to clerify. I am not an amp service professional. My background is 47 plus years in automotive electronics as well as many years as a vintage radio hobbiest, so I understand electronics. It is just the difference in components where I prefer to ask rather than jump in and damage anything. I saw a video where the guy placed a resistor between and diode and transistor that repaired this trouble but, to me, that seems to be a bandaid rather than a repair. Any input would be appreciated. Thanks.
The two inputs when closed form a ground loop. Just insulate one of the tip-ground switches
@@DeadKoby Okay, that clears it up. Thanks...
@@bobamos3628 I THINK that's what I did... trying to remember back can be a bit hazy.
@@DeadKoby yes, I think you had it right. I have run across another suggestion for the same thing. That guy suggested insulting the center contact to stop the hum. I am going to try to get acces to my amp, which is stored behind a number of others and then use some shrink wrap to insulate that contact. I do thank you for the information and your time. After looking at the schematic I may just remove R49 and get the same results..
You are right, because everybody is just fighting symptoms. The real cause for the hum is that there is some kind of sophisticated switching for the power amp, to shut off if there isn't anything connected. If the power amp has a problem, like mine has - asymetric condition causes the hum. Just measure bias at the ceramic resistors of the main transistors. You will see strange things going on. Almost every Frontman has the same problem.