[NJARC] Fwd: Service manual needed for Sears Roebuck 1423 Guitar Amplifier

Wed Jan 11 14:00:10 EST 2017

 Can anyone help Chuck?  Vintage Sears data isn't the easiest to come by and we all know they contracted out most anything with their logo.

Regards,

Joe Devonshire

-----Original Message-----
From: Chuck <cpaci1 at verizon.net>
To: TrainBee <trainbee at aol.com>
Sent: Tue, Jan 10, 2017 9:39 pm
Subject: Re: [NJARC] Service manual needed for Sears Roebuck 1423 Guitar Amplifier

Hi Joe,
I do know that the amp was made somewhere between 1969 and 1971.
And I do know what kind of amp it is. Sears Solid-State LA 35 model 257,14235800 with 50 watts peak power and two 10” 8Ω woofers.
I just don’t know who the manufacturer was and therefore cannot find the service manual for it.

The problem with it is that it sounds like a transistor radio running on half dead batteries. It has heavy distortion, like it’s not getting enough power. 
It also has a 120 cps buzz that’s not from the filter caps. They’re good and the bridge rectifier has all good diodes.
I found several electrolytic caps and several resisters that were WAY off – some over 50% – both caps and resisters.
One would think that after changing all that - - -  there would be at least some improvement... NOPE! not one bit – lol
The voltages look normal too, but I can’t be sure without the technical data.
Does anyone have a small magic wand I could borrow?

73,
Chuck
AC2DP

From: TrainBee 
Sent: Tuesday, January 10, 2017 11:18 AM
To: cpaci1 at verizon.net 
Subject: Re: [NJARC] Service manual needed for Sears Roebuck 1423 Guitar Amplifier

Hi Chuck,

    I ran across this problem with another piece of electronics.  If you ever come across a Kenwood KPS-15 switching power supply, you'll never find it via Kenwood.  It was actually made my Samlex.  I'd guess if you look over the components in your Amp. real carefully, and the chassis, there might just be something to give the real manufacturer away.  Then you'll have to backtrack that information.  This is probably the Heathkit of guitar amps, in that your only clue is to match it with photos to another similar amp.  That's going to be a tremendous amount of work.  I can only imaging the thousands of amps produced over the years and the corresponding variations.  If you've got the years narrowed down, then it would make the research easier.

    So, what's the problem?  Is it more than bad caps?  If it's transisitors, then take the numbers on them and see if you can cross reference them to current parts.  When I was living in NJ, GreenBrook electronics came through for me.  Also, HBF Electronics on State Rd. in Philadelphia might be of help.  215-338-1100. (no website)

Good luck and 73.

Joe   AB1YO

-----Original Message-----
From: Chuck <cpaci1 at verizon.net>
To: TrainBee <trainbee at aol.com>
Sent: Tue, Jan 10, 2017 8:32 am
Subject: Re: [NJARC] Service manual needed for Sears Roebuck 1423 Guitar Amplifier

Hi again Trainbee,
I think you are right... The mgr. date is around the early 70s (69-72).
I heard somewhere that many of the Sears guitar amps may have been made by a company called Dana Electronics – or something like that.
There are no stamps, tags or markings on the chassis at all, Only the tag on the back of the cabinet (see attached)
I did find a schematic identified as “Sears Silvertone Model 1423” (see below), but this is not to the amp I have???

73,
Chuck

From: TrainBee 
Sent: Monday, January 09, 2017 9:57 AM
To: cpaci1 at verizon.net 
Subject: Re: [NJARC] Service manual needed for Sears Roebuck 1423 Guitar Amplifier

Chuck,

    Chances are that someone else made the Amp.  Is there anything else on the chassis that might help to give us a better clue?  Can you narrow the manufacture date down to a decade?  If I had to guess, it just might be a Lafayette from the 1970's.  Does it have a Jensen speaker?  

    This might be some help...   http://www.silvertoneworld.net/

Good luck.

Joe Devonshire

-----Original Message-----
From: Chuck <cpaci1 at verizon.net>
To: Al Klase <ark at ar88.net>; njarc <njarc at mailman.qth.net>
Sent: Mon, Jan 9, 2017 7:26 am
Subject: Re: [NJARC] Service manual needed for Sears Roebuck 1423 Guitar Amplifier

Just remember
Reply = Poster
Reply All = Everyone

_________________________________________________________
Hi and Happy new year everyone!...
I am also in need of a service manual that I haven't been able to find.
Does anyone know where I might find the service manual for a Sears LA 35 
solid-state guitar amp?
Model number 257.14235800 - (see attached)
I tried several combinations of this number, but only got a hit on Sears 
Silvertone 1423 and this is not the right schematic!
Any ideas where I might find one would be much appreciated.
See you at the next meeting.
Thanks,
Chuck
AC2DP

-----Original Message----- 
From: Al Klase
Sent: Saturday, January 07, 2017 1:14 PM
To: njarc at mailman.qth.net
Subject: Re: [NJARC] Service manual needed for Panasonic RF-888

Just remember
Reply = Poster
Reply All = Everyone

_________________________________________________________
Louis,

First off, there's a Panasonic Portables group on Yahoo that you might
find helpful. That's were the manual came from:
https://groups.yahoo.com/neo/groups/panaport/conversations/messages

I wouldn't try to modify the circuitry. Matsushita had excellent
engineers, your chances of outguessing them are quite slim. If they
went from germanium to silicon, it almost certainly improved things.
The PNP to NPN switch will scramble the circuit polarities and bias
resistor values.

If the radio play, leave it alone.

Al

On 1/6/2017 11:58 PM, Louis wrote:
> Just remember
> Reply = Poster
> Reply All = Everyone
>
> _________________________________________________________
> Thanks Al, Joe and Aaron for the help. I had looked and looked for a 
> manual and found others have also inquired about a service manual for the 
> RF-888 w/o any success. Al, you did your homework but - there's always a 
> fly in the ointment, this fly is called, "Panasonic".
>
> The saying that a rose by any other name is still a rose doesn't apply to 
> Panasonic radios, even if they look alike. I have the "RF-888", you 
> provided me with a manual for the "RF-888JB" but wait, there's more! 
> There's also the RF-888LP and the Cougar RF-888 and National Panasonic 
> GX-300 - all basically the same model, different circuitry!
>
> I had stumbled onto this a few days ago by looking at all the web pages 
> with 888 models, lots and lots of them. Think it was RadioMuseum that 
> showed the circuitry of the GX-300 (888JB) it shows two TO-66 style 
> transistors (2SB473 - Germanium PNP) heat sinked by a large piece of 
> aluminum on one board. The RF-888 I have has two TO-126 style transistors 
> (2SC1568 - Silicon NPN) sinked by, ah, a piece of tin foil by comparison. 
> I think they upper the output wattage for the speaker on those other 
> models. Might I be able to get more gain and up my speaker's output 
> wattage or is this not recommended/easy to do?
>
> However, I do believe the manual you found will allow me to adjust the 
> dial scale film on my radio but I will have to look closely at the 
> circuitry before I attempt anything else. Panasonic made some great 
> radios, but each model could have different bands depending on the country 
> it was sold in and therefore different circuits too.
>
> Thanks all.
>
> njarc-request at mailman.qth.net wrote:
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>> Today's Topics:
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>> 1. Re: Service manual needed for Panasonic RF-888 (Aaron Hunter)
>> 2. Re: Service manual needed for Panasonic RF-888 (Al Klase)
>>
>>
>> ----------------------------------------------------------------------
>>
>> Message: 1
>> Date: Thu, 05 Jan 2017 19:47:59 -0500
>> From: Aaron Hunter <ahunter01 at comcast.net>
>> To: Louis <louis2000 at att.net>
>> Cc: njarc at mailman.qth.net
>> Subject: Re: [NJARC] Service manual needed for Panasonic RF-888
>> Message-ID: <586EE93F.1040701 at comcast.net>
>> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>>
>> Looked in the Sam's index, but this model is not listed.
>>
>> Aaron Hunter
>>
>> Louis wrote:
>>> _________________________________________________________
>>> Just picked up an RF-888 and it needs to be disassembled for cleaning 
>>> and repair. I couldn't find a S.M. on eBay so if anyone has one, 
>>> especially if it's already digitized (have one on paper? I'd buy it from 
>>> you) let me know. If anyone has disassembled one to adjust the frequency 
>>> readout ribbon (it's way off) let me know what this entails, thanks.
>>> ______________________________________________________________
>>
>>
>>
>> ------------------------------
>>
>> Message: 2
>> Date: Thu, 5 Jan 2017 20:49:50 -0500
>> From: Al Klase <ark at ar88.net>
>> To: njarc at mailman.qth.net
>> Subject: Re: [NJARC] Service manual needed for Panasonic RF-888
>> Message-ID: <ebccc7c4-b735-5cb5-4315-be06d52018a6 at ar88.net>
>> Content-Type: text/plain; charset="windows-1252"; Format="flowed"
>>
>> A little creative Googling, and I got luck. See attached. - Al Klase
>>
>> On 1/5/2017 7:47 PM, Aaron Hunter wrote:
>>> Just remember
>>> Reply = Poster
>>> Reply All = Everyone
>>>
>>> _________________________________________________________
>>> Looked in the Sam's index, but this model is not listed.
>>>
>>> Aaron Hunter
>>>
>>> Louis wrote:
>>>> _________________________________________________________
>>>> Just picked up an RF-888 and it needs to be disassembled for cleaning 
>>>> and repair. I couldn't find a S.M. on eBay so if anyone has one, 
>>>> especially if it's already digitized (have one on paper? I'd buy it 
>>>> from you) let me know. If anyone has disassembled one to adjust the 
>>>> frequency readout ribbon (it's way off) let me know what this entails, 
>>>> thanks.
>>>> ______________________________________________________________
>>> ______________________________________________________________
>>> NJARC mailing list
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>>> Please help support this email list: http://www.qsl.net/donate.html
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-- 
Al Klase – N3FRQ
Jersey City, NJ
http://www.skywaves.ar88.net/

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