Author Topic: How do I date sunn amps in particular 1200s, scpetre and model T's  (Read 6009 times)

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Offline fender_bender

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how do i date a 1200s and scpetre definitvley. not by knobs or tubes but by serials and codes etc? :?

Offline xsolarusx

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Re: How do I date sunn amps in particular 1200s, scpetre and model T's
« Reply #1 on: February 03, 2009, 07:37:17 am »
Well, get to know what they like, discover similar interests...

Ohh, wait.  You mean determine the date.  haha, awkward.

There should be a date pencilled into the chassis, or a sticker somewhere on the chassis with a date. I don't believe they tracked their models by serial numbers, though.
(2) 73 1st Gen Model T
Late 70's Marshall JCM 800 1960B cab

Offline LEADSOLDERHUFFER

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Re: How do I date sunn amps in particular 1200s, scpetre and model T's
« Reply #2 on: February 03, 2009, 09:48:05 am »
yo have to pull the chassis and the date sticker will be on the side of the chassis, mine was.

Offline fender_bender

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Re: How do I date sunn amps in particular 1200s, scpetre and model T's
« Reply #3 on: February 03, 2009, 01:24:15 pm »
thanks. do i have to remove all the knobs to remove the chassis or does it slide out when the four screws holding the chassis are removed?

Offline djc

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Re: How do I date sunn amps in particular 1200s, scpetre and model T's
« Reply #4 on: February 04, 2009, 07:05:16 am »
the whole chasis will slide out.  be careful when inside.  do not touch stuff.  there are leathal voltages inside a tube amp waiting for those who don't know what to touch or how to discharge it.  another way to date it is by part codes.  easy one is on the transfromer.  others are on the pots, etc.  if there's no pencil on the inside give us the transformer code. 

Offline fender_bender

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Re: How do I date sunn amps in particular 1200s, scpetre and model T's
« Reply #5 on: February 04, 2009, 02:03:44 pm »
the whole chasis will slide out.  be careful when inside.  do not touch stuff.  there are leathal voltages inside a tube amp waiting for those who don't know what to touch or how to discharge it.  another way to date it is by part codes.  easy one is on the transfromer.  others are on the pots, etc.  if there's no pencil on the inside give us the transformer code. 

thanks for the warning, as it always important to mention when pulling a chassis on a tube amp.
 
I learned the hard way (as per usual) when I would hold my guitar neck while plugged into my former '67 super reverb with it's orginal two prong plug and switch on some other amp to warm it up. I would effectivly complete the circuit there. Needless to say I would do it quite often mistakenly, it was weird sensation. I would hate to touch a circuit that hasn't had it's caps discharged, btw something I haven't learned to do yet but had read about it.

Offline LEADSOLDERHUFFER

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Re: How do I date sunn amps in particular 1200s, scpetre and model T's
« Reply #6 on: February 05, 2009, 03:23:21 pm »
THIS INFO COMES FROM A RELIABLE SOURCE!

"Here is a safety tip.  Go to Radio Shack and get some clip leads.  These are 12" wires with little alligator clips on each end.  Cut the lead in half and solder a 470 2 watt metal oxide resistor trimmed to size to each end of the clip leads.  Cover the resistor and solder connections with shrink tube.

Use this resistor to drain the voltage in the filter caps by clipping one end of this device to ground and the other end to the positive side of the filter cap.  Leave the clip lead in place for 30 seconds on each cap.  Now it is safe to work on the amp or remove the old caps. "
WARNING IF YOU DON'T KNOW WHAT ALL THIS MEANS, YOU PROBABLY SHOULD'NT BE MESSING AROUND WITH YOUR AMPS INSIDES.
USE AT YOUR OWN RISK! YOU'VE BEEN FOREWARNED.

Offline fender_bender

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Re: How do I date sunn amps in particular 1200s, scpetre and model T's
« Reply #7 on: February 05, 2009, 05:35:30 pm »
ive read that there is a way to drain the caps using a multimeter this way you can determine how much charge is remaining in the caps, and watch/or read the meter as they are draining.

Offline LEADSOLDERHUFFER

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Re: How do I date sunn amps in particular 1200s, scpetre and model T's
« Reply #8 on: February 05, 2009, 09:15:39 pm »
seems like it'd be hard on your meter.
thats how its done. believe it or not.
check it afterwards, i'd think the impedance on your meter would let the charge out to fast and likely damage your meter.
somebody correct me if i'm wrong.

Offline mckinnon audio

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Re: How do I date sunn amps in particular 1200s, scpetre and model T's
« Reply #9 on: February 05, 2009, 10:43:39 pm »
  Hi there,if your meter is on the 600v DC range,or higher,you can't hurt it.Typically the input impeadence of meters is pretty high,you won't be drawing any significant amount of current,virtually nil.If the meter is on a lower range than your B+ voltage,you might damage the meter movement or shunt resistors.Be careful,Mel.

Offline EdBass

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Re: How do I date sunn amps in particular 1200s, scpetre and model T's
« Reply #10 on: February 06, 2009, 05:47:10 pm »
As far as  discharging caps goes, I think the best method (particularly for big electrolytics) is to ground them with your tongue while standing on a wet concrete slab barefoot.
Works every time, and you definitely know when it's discharged and safe to work on.

Offline LEADSOLDERHUFFER

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Re: How do I date sunn amps in particular 1200s, scpetre and model T's
« Reply #11 on: February 06, 2009, 06:48:04 pm »
a copper lightning rod hammered 7 feet into the ground would assist the electron flow if you decided to go this route and wanted to be as prepared as possible to manually close the circuit with your waffle trap.


Offline djc

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Re: How do I date sunn amps in particular 1200s, scpetre and model T's
« Reply #12 on: February 06, 2009, 07:27:35 pm »
 ha ha!:lol:

Offline fender_bender

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Re: How do I date sunn amps in particular 1200s, scpetre and model T's
« Reply #13 on: February 08, 2009, 06:48:43 am »
  Hi there,if your meter is on the 600v DC range,or higher,you can't hurt it.Typically the input impeadence of meters is pretty high,you won't be drawing any significant amount of current,virtually nil.If the meter is on a lower range than your B+ voltage,you might damage the meter movement or shunt resistors.Be careful,Mel.

so there is technic for using a multimeter is that correct?