| K200A-2 [message #15932] |
Thu, 30 June 2011 18:35  |
cassent5150
Messages: 341
Registered: August 2009
|
Senior Member |
|
|
OK, I got a real "HUM DINGER" here to restore. I dont know whats all still good yet. I need the full compliment of schematics for this thing with layouts if anyone has them. I also neeed the values on the transformer and rectifier outputs. I have taken before pictures of this project this time and posted them to the link below. It was real ugly inside when I opened it up.
http://www.flickr.com/photos/57807996@N04/sets/7215762696248 5469/
Steve C
|
|
|
|
|
|
| Re: K200A-2 [message #15934 is a reply to message #15933] |
Sat, 02 July 2011 10:47  |
cassent5150
Messages: 341
Registered: August 2009
|
Senior Member |
|
|
I pulled the covers on the transformer and she's like new inside. I hooked it up to the rectifier (I soldered the tab back on the old original one) and did some testing. I have 29 VAC on both leads from the center tap and out of the rectifier I have 26.5 VDC plus and minus tabs. I dont have a schematic to tell if thats correct but it seems to be operating properly at this point. Got a little cosmetic damage on the covers and mounting tags I'll correct and I should have it mounted to the new chassis bottom with the filter caps and rectifier this weekend and maybe started on the driver board. Please let me know if those transformer and rectifier values are correct. Thanks Steve C
Steve C
|
|
|
|
|
|
|
|
| Re: K200A-2 [message #15991 is a reply to message #15933] |
Sun, 31 July 2011 20:36 |
cassent5150
Messages: 341
Registered: August 2009
|
Senior Member |
|
|
OK, I'm gettin my but wooped on this thing. I got the driver board up and running. Regulators are pushing right at 24.5 volts plus and minus. Both channels are working, but it seems that is all I can do. I can't get the effects boards to work. The reverb will make a faint rattle if you tap on the tank springs and the tremolo/Vibe doesn't work at all. Thats where I'm at with it at the moment. I recapped it and checked the transistors and diodes and everything checks out with my multimeter tester. Any ideas cause I'm out of them. I looked all the traces over for bridging and cracks or broken spots and the thing really looks good. I even cleaned the pots real good. I think maybe I need to step away from this one for a bit and cool down. I been testing it out as I go along and the thing is super warm sounding like my old Frank. There is definite difference in the tone quality over the B models I've been working with. Also, I noticed that there is a 1/4 inch line out Jack on the front of this one (K200A-2) that is between the low input of the right (NO EFFECTS) channel and the Bass control of that channel. Any ideas why? It is connected via a shealded cable to the output of the right channel.
Steve C
|
|
|
|
| Re: K200A-2 [message #15994 is a reply to message #15932] |
Mon, 01 August 2011 12:00 |
chicagobill
Messages: 2006
Registered: April 2003
|
Senior Member |
|
|
Nice job on the chassis, is the new bottom panel doubling the old one or did you cut the old one out?
It looked to me like that amp was under water for a long time and when the pc boards get that wet, all of the solder joints become suspicious.
Whatever ate through the aluminum chassis will also eat through the solder and the pc board traces. I would suggest using a continuity tester on all of the traces and I might even suggest removing and replacing all of the solder connections on the boards and resoldering them all.
|
|
|
|
|
|
| Re: K200A-2 [message #15997 is a reply to message #15996] |
Mon, 01 August 2011 19:58 |
cassent5150
Messages: 341
Registered: August 2009
|
Senior Member |
|
|
I cut out the corroded bottom just leaving enough at the edges to rivot the new panel in. I used the old piece at a templet to drill all the mounting holes and then tossed it in the trash. The thing looks like it had something spilled in it that was corrosive to alluminum or maybe salt water. I dont think it was under water, but something was sitting in the bottom just touching the bottom edge of the driver and both pre amp circuit boards. The left effects channel PC- 102 was working fine as well as the PC-102 on the right channel, but I replaced all the white mallory caps anyway on both those boards. Same goes with the driver board and the 2 regulators, I replaced all the white mallorys and transistors and they worked fine. I didn't replace any transistors on the effects board, just the white mallorys. I picked up another Frank chassis right after I completed the first posting on the progress of this amp so I set this aside to look into the Frank. Got it working and waiting on my #48 bulbs to get here so I can wrap it up. I tested the trem out with a flashlight and waving a LED light cross the sensor can make some pretty cool sounds. There is no tag on it so I dont know exactly what model it would be. It has reverb and tremolo on the left and standard controls on the right so I guess that would make it a 695-RV or RT wouldn't it?
Steve C
|
|
|
|
| Re: K200A-2 [message #15999 is a reply to message #15932] |
Tue, 02 August 2011 12:14 |
chicagobill
Messages: 2006
Registered: April 2003
|
Senior Member |
|
|
The Frank would be an ?95-RV, Reverb and Vibrato.
The number would be based upon what other features like speaker brand and number the amp originally came with. The number was actually the retail list price of the amp when it was new. Check out the literature section and look at the Frank amps to see what I mean.
If you look at the schematic for the Frank vibrato section, the first transistor has outputs from both the collector and the emitter legs. The collector feeds the next stage via an 0.005uF capacitor and the emitter feeds the next stage through the photocell resistor. The signals at the C and E legs are 180 degrees out of phase with each other. When the two signals are are mixed, you get pitch shifting vibrato.
|
|
|
|
| Re: K200A-2 [message #16075 is a reply to message #15932] |
Thu, 15 September 2011 13:07 |
conductortom
Messages: 96
Registered: July 2010
Location: Okla
|
Member |
|
|
Damn Steven, I just bought the twin brother to that one! Mine is not quite that bad of shape, but damn close. It did have JBL's D130f's which is why I bought it. Good luck on yours'
Tom
|
|
|
|
| Re: K200A-2 [message #16076 is a reply to message #16075] |
Thu, 15 September 2011 18:46 |
cassent5150
Messages: 341
Registered: August 2009
|
Senior Member |
|
|
Great!!! or wait I guess that could be "Sorry to here that". Good for the JBL's. I kind of been out of the loop the past month. I got sick and found out I had pancreatic cancer so I spent the last 3 and half weeks at the MAYO ClINIC in Rochester MN getting a treatment plan so I might live a little longer and wrap things up here in Texas. I just repainted the back side of the faceplate for the K200A today. I'm trying to get that one ready to sale. I got everything working with the exception of the weak trem/vib. I still may straighten that out before putting it up for sale. I bought a Blue sparkle case off ebay for it so it should look as good as it sounds. I have to admit the A models are a bit warmer in overall sound, but I like the B series stability far as from a service perspective is concerned. I need to get going on 2 frank cabinets I need to build and Tuck N Roll, one cascade sparkle and the other red sparkle. I got the material and just need to find the time to do the work. I've got a 495 Frank chassis thats says Black and the other Frank chassis is a 5 transistor "Very early ROSS MFG. model" that is going to be Red sparkle and both working good.
Steve C
[Updated on: Thu, 15 September 2011 18:57] Report message to a moderator |
|
|
|
| Re: K200A-2 [message #16081 is a reply to message #16076] |
Fri, 16 September 2011 12:54 |
conductortom
Messages: 96
Registered: July 2010
Location: Okla
|
Member |
|
|
Sorry to hear about your cancer. Hope it goes well for you.
I bought an 6 transistor head awhile back. 745 pa, I think. Needs reverb worked on, but plays good. Getting so many that I have a hard time deciding which amp to play! LOL. Love it.
|
|
|
|
| Re: K200A-2 [message #16084 is a reply to message #16081] |
Fri, 16 September 2011 18:42 |
cassent5150
Messages: 341
Registered: August 2009
|
Senior Member |
|
|
Yea, but thats a problem that only a select few have the privaledge to deal with. I take that challenge every time I load out for a gig. I have my favorites I'll admit but thats usually overruled by whats needed to get the full sound I'm trying to get. I needed the last cabinet I scored a month ago for my bass section. A single 18" (I have a sweet Electrovoice EVM-18 waiting to replace that CTS) as soon as I get a good charge on my power screw driver, theres got to be 100 screws or more in the back of this T&R Cab. Its not the folded horn style, just straight forward like the standard 215 only the cabinet is larger. I already tried the K-IV on it and she'll take everything hanging off the walls so this should do the trick. I still got to get the Frank chassis (695-PA) in a cascade cabinet (my next project cabinet and T&R job)so I have the complete cascade Frankenstein on the matching 3X15 cab.
Steve C
|
|
|
|
|
|
| Re: K200A-2 [message #16086 is a reply to message #16085] |
Fri, 16 September 2011 18:49 |
cassent5150
Messages: 341
Registered: August 2009
|
Senior Member |
|
|
Thanks, we just have to keep going on with the game and deal with the cards we draw along the way. They haven't stopped reshuffling yet and the dealers a good friend so I'm still in the game I guess till he calls me home.
Steve C
|
|
|
|
| Re: K200A-2 [message #16088 is a reply to message #15932] |
Fri, 16 September 2011 19:00 |
RickBlacker
Messages: 133
Registered: October 2008
Location: Oregon
|
Senior Member |
|
|
Hi Steve,
We've never chatted in any posts, was reading yours, sorry to hear about your condition! Sounds like you have your spirits high looking to the all mighty for guidance and strength.
My amp : K100C-8
|
|
|
|
|
|
|
|
|
|
| Re: K200A-2 [message #16111 is a reply to message #15932] |
Wed, 21 September 2011 09:54 |
Kustom_Bart
Messages: 601
Registered: October 2010
Location: Greenville, MichiGUN
|
Senior Member |
|
|
Fight it hard my friend! I hope all turns out well and you kick cancers ass!
Best of wishes and prayers send your way!
|
|
|
|
VintageKustom.com
Search
Help
Members
Register
Login
Home
]