| Frankin cascade [message #3983] |
Sun, 04 April 2004 12:21  |
biggroove
Messages: 3
Registered: April 2004
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I picked up this Frankenstein thats dead mint in a package deal. The color is Cascade,I don't have it with me right now, but the model is something PA. Its 2 channels 2 inputs each, 1 has reverb the other dosn't, it also has only 1 spreaker jack. Is this a pa amp? If so what else could it be used for? Please help, anybody.
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| Re: Frankin cascade [message #3985 is a reply to message #3984] |
Sun, 04 April 2004 16:49  |
biggroove
Messages: 3
Registered: April 2004
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Thanks man, I did plug it into a 4/12 cab, turned it up, and it really crunched nicely, not distortion but clean Fender style crunch. its so cool and minty looking, I'd like to find a mathing 2/12 cab. Anybody ????
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| Re: Frankin cascade [message #3987 is a reply to message #3985] |
Sun, 04 April 2004 22:39 |
ET
Messages: 146
Registered: October 2000
Location: Charlotte NC
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congrats on the your kustom acquisition...The frank, early heads, like many stage amps were often used double duty..handling, bass, keys, guitar, anything that could be plugged in... and 2 channels were all that were offered by kustom at that time...I'm guessing that's one of the reasons Bud offered the hi frequency cab add-on the next year..and yes, there were columns available in true Sure PA style fashion. Bud was busy growing his business based around his fundamental bass amp so I do understand how he would have added reverb and taken on the PA support piece early on.
As for a cab, those 11 pleat "frank " heads are a tad wider than the later 2x12 cab models so it can look a bit awkward on top of one...their original cabs were all 2x15 models 11 pleats wide, and I'll tell ya, the earlier no-port 2x15 cabs actually scream for guitar..sound more like a truly nice black face pre-CBS fender twin..its a tone worth checking out, and if you're going to own a nice cascade rig, I'd recommend it be original..you can see mine on kustomplayer.com under the Frank section..its the cascade rig including the hi-freq cab as originally intended.. I have my bud Bryan to thank for making this dream rig possible...anyway, welcome to the site, and kustom mania... Play Loud! ET
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| Re: Frankin cascade [message #4045 is a reply to message #3987] |
Fri, 16 April 2004 02:18 |
jimi
Messages: 46
Registered: February 2003
Location: Redding Ca
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I also have a 745PA. Mine has a grill on back instead of the solid backs I've seen. Is this just on the PA series or early amps in general/ 1st post- love the site!Great support!
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| Re: Frankin cascade [message #4046 is a reply to message #3983] |
Fri, 16 April 2004 02:33 |
jimi
Messages: 46
Registered: February 2003
Location: Redding Ca
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I bought a 745PA and am wondering if only reverb and without tremelo has better tone than the models that have both since they are without the extra circuit. Also, my amp has a grill on the back instead of the solid backs I'm used to. Is that on all early models or just the PA series? Only one speaker out too.
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| Re: Frankin cascade [message #4050 is a reply to message #4046] |
Fri, 16 April 2004 10:02 |
jimi
Messages: 46
Registered: February 2003
Location: Redding Ca
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One more thing that was brought up but not clarified, what exactly does "modified" K200 mean in regards to the 745PA heads
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| Re: Frankin cascade [message #4052 is a reply to message #4050] |
Fri, 16 April 2004 11:35 |
chicagobill
Messages: 2006
Registered: April 2003
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The PA (Public Address) version of the K200 was a standard K200 head with added reverb. The reverb only works on the left side or first channel of the amp. To find out what the difference in tone is, compare the right channel with the left. The signal from the right pre-amp goes directly to the power amp, and the signal from the left pre-amp goes though the reverb board.
As for the back, all of the Frankenstein heads that I have ever seen have the perforated metal back panel with one speaker jack. This is due to the fact that the output transistors are mounted on the back panel of the amp and need ventilation to keep them cool. The later B-series moved the transistors to the bottom panel, thus eliminating the need for the perforated panel.
Read some of the older threads here, and you'll find much more information regarding your amp.
Bill
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| Re: Frankin cascade [message #4053 is a reply to message #4052] |
Fri, 16 April 2004 21:04 |
jimi
Messages: 46
Registered: February 2003
Location: Redding Ca
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Thanks Bill,I forgot to ask about jumping the 2 channels. Also someone was talking about inputs being modified for mics. On the PA 745 heads are the inputs low and high
like on the later 100s or modified for mics somehow? Did the Frankinsteins have a different circuit than later models?
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| Re: Frankin cascade [message #4119 is a reply to message #4053] |
Tue, 27 April 2004 04:05 |
jimi
Messages: 46
Registered: February 2003
Location: Redding Ca
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On my 67' 745PA the inputs are set back so the nut is recessed in the plexi and tightens directly to the metal. Is that normal for the old heads or did somebody remodel mine?
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| Re: Frankin cascade [message #4124 is a reply to message #4119] |
Tue, 27 April 2004 11:49 |
chicagobill
Messages: 2006
Registered: April 2003
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Senior Member |
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Jimi:
There usually is a capacitor on one of the input jacks that cuts the lows out for the "high" input jack, on the Frankenstein heads. I say usually, because only 2 of my 3 heads have this. If you open up the head and look at the back of the input jacks, you'll see a small capacitor wired between the two jacks if you have one. Actually, just plug a guitar in each of the jacks and listen. The difference in bass response is quite noticeable.
It's been awhile since I've taken the plexi panel off of one, but I seem to remember that only 3 or 4 of the control nuts are used to hold the panel on, so your input jacks are mounted correctly.
The early K200 Frankenstein series amps are entirely different from the later B series amps. The entire amp was re-designed and re-engineered to be mass produced. The one major change that may be responsible for the biggest change in tone, was the re-design of the power amp. The Frankenstein power amp uses a transformer in the driver/phase inverter stage, while the B-series does not. The B-series also added missing features to the amps, like foot switchable reverb and vibrato (among other things).
Bill
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| Re: Frankin cascade [message #4129 is a reply to message #4124] |
Tue, 27 April 2004 19:44 |
jimi
Messages: 46
Registered: February 2003
Location: Redding Ca
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Thanks for responding Bill, I really am hooked on old Kustom amps. I sold my 68' "100" and missed it alot, then I bought this Frank 745 PA. Problem is channel 1 with reverb has signal when you first fire it up, albiet weak, and then it farts out with no volume or reverb. The other channel has good signal but sounds overdriven compared to my old "100". Is that normal? Not distorted though. Is that the diff in circuit design? The reverb can looks fine inside. No leaky capacitors and all wiring looks original and in good shape. Anybody?
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| Re: Frankin cascade [message #4131 is a reply to message #4129] |
Tue, 27 April 2004 23:07 |
jimi
Messages: 46
Registered: February 2003
Location: Redding Ca
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Almost forgot, does anybody know where to get a Frank 745PA manual/schematic? Thanks, jimi
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| Re: Frankin cascade [message #4136 is a reply to message #4129] |
Wed, 28 April 2004 12:10 |
chicagobill
Messages: 2006
Registered: April 2003
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Senior Member |
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Jimi:
If you turn down the reverb control to zero, and the signal dies, then the problem lies in the pre-amp. If the signal is ok then the problem is in the reverb circuit.
Over all the sound should not be distorted. I think that the Frankenstein heads sound a bit warmer than the later B-series heads.
Does the distortion change with different settings of the treble and bass controls? The feedback design of the treble control makes it prone to oscillate as the circuit ages. The oscillation usually is too high to hear, but will cause distortion or other problems. Sometimes just moving the wires going to the controls can fix this.
There are two caps in the power supply that seem to have a high failure rate in the Frank heads, but it depends on how old your amp is. The caps are located on the FX board and the driver/regulator board. They are both 500 mfd, and are either molded black plastic or cardboard sleeved aluminum can types. Of the black plastic ones that I have seen, 75% of them have dried out and opened up. The cardboard sleeved ones don't seem to fail in the same way. So be sure to check these caps.
Bill
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| Frank 745 PA [message #4140 is a reply to message #4136] |
Thu, 29 April 2004 00:22 |
jimi
Messages: 46
Registered: February 2003
Location: Redding Ca
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Hey Bill I replaced the 2 500 caps and now I've got full clean volume on both channels. When the reverb knob is turned down volume goes down. Also there's no reverb at all and as I said before the can looks good. I really scared myself after replacing caps. I turned the amp on and had forgotten to bolt down the main pc board frame that I had taken loose to clean under it. Needless to say it lost ground and made this terrible loud unbelievable noise and I thought it was gonna blow! How dumb is that? To make matters worse I plugged the reverb can in backwards for another round of unnerving noise. No smoke or anything and it fired up and sounded good with mabe a little louder hum, I can't tell at this point. Could I have damaged the amp doing this stupid stuff or just possibly the speaker. Totally frazzled,Jimi
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| Re: Frank 745 PA [message #4141 is a reply to message #4140] |
Thu, 29 April 2004 00:43 |
jimi
Messages: 46
Registered: February 2003
Location: Redding Ca
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I was mistaken on the last post. I turn the reverb knob up and the volume on channel 1
(the reverb channel)goes down.
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| Re: Frank 745 PA [message #4142 is a reply to message #4141] |
Thu, 29 April 2004 12:36 |
chicagobill
Messages: 2006
Registered: April 2003
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Senior Member |
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Jimi:
Slow down and work carefully is what I always have to remind myself when I do dumb stuff. I don't know if you did any damage, but if it's working probably not.
The reverb control is like a balance control, CCW -all straight signal, CW- all reverb signal. So if the reverb isn't working it will act like a reverse volume control for the straight signal. Do you have a ohm meter? If you do, check the resistance of the reverb tank transducers. They both will read somewhere around 200 ohms to ground. If one is open, check for broken wires inside the tank, between the transducer coil and the rca jacks. This is the number one cause of reverb problems in all spring reverb amps! If the tank is ok, then you will need to troubleshoot the reverb circuit.
First check to see if the return circuit is working, by turning up the reverb control and lightly shaking the tank. You should hear the springs boinging thru the speakers. If not, check the cables for continuity and then check the transistors on the pc board. Also check all of the solder connections etc. on the reverb board. Don't forget to check the wires going to the reverb control.
If the return circuit is working, then the problem is in the drive section. If the transistor is ok then I'd suspect the 1000 mfd cap going to the tank.
Bill
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| Re: Frank 745 PA [message #4283 is a reply to message #4142] |
Mon, 31 May 2004 10:49 |
jimi
Messages: 46
Registered: February 2003
Location: Redding Ca
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Just got a L995RV Frank and don't see the 1000 mfd cap that goes to the reverb. at the reverb output there's only .002 mfd cap.
I don't see a 1000 anywhere. Is this something on pre 1967 Frank heads because I don't see it on my 745PA either? Thanks for
all the help, Bill and Steve!
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| Re: Frank 745 PA [message #4289 is a reply to message #4283] |
Tue, 01 June 2004 11:12 |
chicagobill
Messages: 2006
Registered: April 2003
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Senior Member |
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Jimi:
Congrats on the new head!
I mis-typed the value for the reverb drive cap, it is a 10mfd not 1000! It should be the last thing between the transistor collector and the reverb "IN" cable. There should be an 0.02 cap at the input of the reverb return circuit.
Bill
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| Re: Frank L995RV [message #4290 is a reply to message #4289] |
Wed, 02 June 2004 01:07 |
jimi
Messages: 46
Registered: February 2003
Location: Redding Ca
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Channel 1 with verb and trem on my L995RV has no signal except an increasing buzz as you turn up the revrb control. Channel 2 sounds great but does'nt seem to reach full volume. Pan has crashing noise but no signal. Where do I start? PS Both 500 mfd caps are changed. In an earlier email I asked about reverb and driver section . Are they 2 different pc boards or? Thanks for all your help Bill, jimi
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| Re: Frank L995RV [message #4292 is a reply to message #4290] |
Wed, 02 June 2004 11:51 |
chicagobill
Messages: 2006
Registered: April 2003
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Senior Member |
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Jimi:
On the 95 series heads, the driver/voltage regulator section is the small pc board that is mounted on the rear panel with the power transistors. On the PA or RV heads, the effects board is mounted on the left side as you face the front of the chassis.
If you have reverb crashing but no straight signal, I'd check the pre-amp section first. If there is no signal going into the reverb section, all you will get is hum. The usual things to check are loose components, bad solder joints, transistors and caps. I haven't seen any specific single problem part in the 95 pre-amps. One of my 95 heads with similar problems to yours, turned out to be a broken pc board trace from the output of the pre-amp. I found this only after spending hours checking components. So don't overlook the simple things!
Bill
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| Re: Frank L995RV [message #4303 is a reply to message #4292] |
Fri, 04 June 2004 02:59 |
jimi
Messages: 46
Registered: February 2003
Location: Redding Ca
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Member |
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Bill, will 470mfd/35 caps work in place of the original 500mfd/25's On the effects and driver boards in the L995RV?
Radio shack and the only other source in town don't carry
500's anymore for some reason. Thanks again, jimi
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| Re: Frank L995RV [message #4304 is a reply to message #4303] |
Fri, 04 June 2004 11:56 |
chicagobill
Messages: 2006
Registered: April 2003
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Senior Member |
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Jimi:
The 470 mfd caps are the modern standard value, and will work fine as replacements for the 500's.
The glass tube is a Clairex photocell. The photocell and the light bulb are part of the vibrato circuit, which is basically a single stage phase shifter. I have found that changing the photocell will dramatically improve the vibrato depth.
I also thought that a quick way to check your pre-amp is to bypass the RV board, and send the signal directly to the power amp, just like the right channel is.
Bill from Chicago
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| Re: Frank L995RV [message #4305 is a reply to message #4304] |
Fri, 04 June 2004 21:06 |
jimi
Messages: 46
Registered: February 2003
Location: Redding Ca
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Member |
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Sorry to bother but I don't see were channel 2 goes directly to the power amp. Looks like power comes in at channel 1. Theres a red and a blue coming from driver board to channel 1 board and a green wire coming from to corner of channel 1 board to rv board. Stumped! jimi
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| Re: Frank L995RV [message #4307 is a reply to message #4304] |
Sat, 05 June 2004 12:18 |
jimi
Messages: 46
Registered: February 2003
Location: Redding Ca
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I allowed the red hot wire that goes from the driver board to the effects board to touch the chassis and it sparked causing the one good channel (right) to go out and in it's place a loud buzz through the speaker. I replaced the 2 transistors that go to each transistor and the buzz diminished. What did I fry. No smoke, but a faint burning smell coming from the driver board area. Fit to be tied. What else could happen? On top of all this I found a 25 amp speaker fuse where the 5 amp should have been. Would that have been the fuse that would have saved me? Sould have checked the fuses first thing! Well....... jimi
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| Re: Frank L995RV [message #4308 is a reply to message #4307] |
Sat, 05 June 2004 14:59 |
chicagobill
Messages: 2006
Registered: April 2003
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Senior Member |
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Jimi:
Sorry to here about the sparks! I apologize if my advice has steered you wrong in any way, but as I don't know the level of your abilities, it's kind of hard for me to know what to advise you to try to do.
The driver board also contains the power supply/voltage regulator which supplies the low voltage (25v) to the pre-amps. I would guess that you cooked something in the power supply/regulator circuit. That would definitely cause the symptoms that you describe. Do you have a copy of the schematic? It would probably help. Try to check everything on the board that you can. Removing the board is a real pain, as it is mounted to the back panel by way of the regulator and driver transistors. The first thing I would check, would be the big output transistor (part # 36892) and the three small transistors in the regulator circuit. If you actually smelled something burning, then check all of the resistors.
Of course, do all of this only after unplugging the amp and if you feel that you have the necessary skills to do this.
The speaker fuse should be a 5 amp fuse, but this will really only protect the speakers in the case of an output transistor failure or overload. This would not have helped with the short circuit.
Bill
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| Re: Frank L995RV [message #4310 is a reply to message #4308] |
Sat, 05 June 2004 17:21 |
jimi
Messages: 46
Registered: February 2003
Location: Redding Ca
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what value is part #36892? Is it a.022 reddish color? I faxed Steve for a schematic but it has not shown up yet. I replaced a transistor and the 90mfd cap at the left top of the driver board. Now the amp is quiet, you can hear signal through speaker but no volume from inputs. Where on the driver board is the regulator circuit located, are the three transistors the parallel ones at the top right of the board? Anyway, if you could describe the the big transistor and it's value I could probably find it. Thanks, jimi
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| Re: Frank L995RV [message #4311 is a reply to message #4310] |
Sat, 05 June 2004 20:35 |
VinceG2
Messages: 26
Registered: April 2004
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Junior Member |
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36892, is as ChicagoBill said, an output transistor, not a capacitor as you are describing. The transistor's NTE part number equivient is NTE130. You can get them at mouser for $4.06. However, I think these are supposed to be in pairs, in which case, you should really get a matched pair (replace both at once), for best results. NTE130MP would then be used (2 NTE130s sold together.). Mouser has that for $9.01.
Industry Number : 36892
NTE Device Number: NTE130
T-NPN,SI-AF POWER OUTPUT,,TO-3
Industry Number : NTE130MP
NTE Device Number: NTE130MP
MATCHED PAIR OF NTE130,TO-3
Personally, it sounds like you are trying to fix this by trial and error. If you don't know what transistors and parts look like, I'd highly suggest having a professional work on the amp, as you can cause further damage trying to do things randomly.
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| Re: Frank L995RV [message #4313 is a reply to message #4311] |
Sun, 06 June 2004 12:27 |
jimi
Messages: 46
Registered: February 2003
Location: Redding Ca
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Member |
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Thanks for the advice, I'm having a good solid state tech chk it out next week. I thought I could figure it out with help from here but you need to be more familiar with solid state
curcuitry than I am. One more question so I don't do any other damage. From the paper output transformer to the driver board, I think the blue wire was physically above the red wire. When I took the driver board off the back of the chassis both those wires came loose. They looked like after the fact cold solder joints and I was'nt pulling. Anyway, what order as far as above or below are the blue and red output wires attached to the driver board on the 95RV Frank head. I promise it's going to the tech on Mon. Jimi PS, a close up digital photo would help.
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| Re: Frank L995RV [message #4315 is a reply to message #4308] |
Sun, 06 June 2004 19:05 |
jimi
Messages: 46
Registered: February 2003
Location: Redding Ca
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I'm going to seek professional help, with the amp and mabe my addiction too! Just one thing I need to know right away. Blue and red wires from the paper transformer came loose from the driver board while removing same. (I think due to cold solder joints) Does blue go to lower terminal and red to upper terminal or other way around? Thanks, Jimi
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| Re: Frank L995RV [message #4317 is a reply to message #4311] |
Sun, 06 June 2004 22:18 |
jimi
Messages: 46
Registered: February 2003
Location: Redding Ca
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Vince, I'm really glad you posted in responce to my mess. I'm taking your advice. Just really need to know right away which wires go where from the paper transformer (output?)next to the driver board. red and blue wires come out and attach one above the other. Red on top and green below? That's what seems logical looking at circuit trace. thanks, jimi
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| Re: Frank L995RV [message #4319 is a reply to message #4317] |
Mon, 07 June 2004 07:49 |
VinceG2
Messages: 26
Registered: April 2004
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Junior Member |
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Jimi, I don't know the answer to that question. I have a K-250 amp, not a Franklin head. I was able to answer about the transistors because they are the same as what's used in the K-250.
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| Re: Frank L995RV [message #4321 is a reply to message #4317] |
Mon, 07 June 2004 11:55 |
chicagobill
Messages: 2006
Registered: April 2003
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Senior Member |
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Jimi:
As your tech will need to know how to put it back together, I will get an answer to your driver transformer question tomarrow. As I took apart one of my 95RV heads this weekend to find out where things are located, I'll look at mine.
****(I checked it out, the red is on top and goes to the power supply regulator transistor, the blue wire goes to the driver transistor.)****
Vince, I couldn't agree with you more. Inexperienced hands can sometimes do far more harm than good. On a web board like this one, it's hard to know how qualified someone is. Perhaps we should all re-think the giving out of repair advice here. Bill from Chicago
[Updated on: Mon, 07 June 2004 13:06] Report message to a moderator |
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| Re: Frank L995RV [message #4327 is a reply to message #4321] |
Mon, 07 June 2004 21:31 |
jimi
Messages: 46
Registered: February 2003
Location: Redding Ca
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I'm not that inexperienced, I can understand schematics, I can read values and know the difference between capacitors and transistors and resistors. When you said big transistor I thought you meant a transistor on the driver board because you did'nt refer to it as an output transistor or I would have known what you were talking about.I've made a some of dumb mistakes but but I've learned from them. You said you've made some yourself albiet you are much more experienced than myself. I'm learning quick and am starting to understand the curcuit board tracing and the way it works. I'm somewhat familiar with tube amps but solid state is new to me. My point is, I hope I haven't ruined it for other do-it-yourself Kustom techs and I think it would be a shame if you did'nt dispence your wisdom on the webboard because this is what the forum is all about. I did'nt smoke the amp or electrocute myself. My track record is I did'nt know the preamp board frames grounded the amp, hooked up the reverb pan leads wrong, and let the hot lead from the driver touch ground for an instant. Sorry about bothering you so much. Thanks jimi
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