Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: tomof63 on February 24, 2021, 04:36:07 pm

Title: '69 Fender Bandmaster Reverb Capacitor Question
Post by: tomof63 on February 24, 2021, 04:36:07 pm

Hi All,

Recently purchased a mostly stock '69 Bandmaster Reverb. It had 2 prong plug and all original caps. I couldn't locate one of the capacitors a 25uf 25V in the vibrato circuit. According to the one and only layout diagram (thanks Hoffman!) it should have been on the main board. I finally located it, it was on pin 3 of V5 and connected to the sleeve of the vibrato jack. I should've taken a pic of it but I didn't. I pulled the old cap out and now I'm second guessing myself on the orientation of the polarity. Does anyone know if the + should be toward the pin or the sleeve of the vibrato jack?

Thanks in advance!!

Title: Re: '69 Fender Bandmaster Reverb Capacitor Question
Post by: tomof63 on February 24, 2021, 04:45:17 pm

Or should I just solder in a replacement capacitor on the board where it is shown in the layout diagram? I may have answered my own question. :smiley:

Title: Re: '69 Fender Bandmaster Reverb Capacitor Question
Post by: jordan86 on February 24, 2021, 04:47:30 pm

could you post your schematic or layout?

Title: Re: '69 Fender Bandmaster Reverb Capacitor Question
Post by: jordan86 on February 24, 2021, 04:49:21 pm

Is this it? https://el34world.com/charts/Schematics/Files/Fender/Fender_bandmaster_reverb_aa1069_schem.pdf

Title: Re: '69 Fender Bandmaster Reverb Capacitor Question
Post by: jordan86 on February 24, 2021, 04:52:19 pm

Those original fenders often had a dual cap in that spot. Two caps inside one unit. Two positive leads but one negative to ground. If your replacing it with two individual caps you’ll have two separate negative leads to ground.

Title: Re: '69 Fender Bandmaster Reverb Capacitor Question
Post by: tomof63 on February 24, 2021, 05:06:30 pm

Yes that's the same schematic and layout.
It had just one white Mallory 25uf, not 2 in that position as is shown on the layout. I just don't remember which direction I should wire in a new one.

Title: Re: '69 Fender Bandmaster Reverb Capacitor Question
Post by: 2deaf on February 24, 2021, 05:22:57 pm

Quote from: tomof63 on February 24, 2021, 04:36:07 pm

Hi All,

Recently purchased a mostly stock '69 Bandmaster Reverb. It had 2 prong plug and all original caps. I couldn't locate one of the capacitors a 25uf 25V in the vibrato circuit. According to the one and only layout diagram (thanks Hoffman!) it should have been on the main board. I finally located it, it was on pin 3 of V5 and connected to the sleeve of the vibrato jack. I should've taken a pic of it but I didn't. I pulled the old cap out and now I'm second guessing myself on the orientation of the polarity. Does anyone know if the + should be toward the pin or the sleeve of the vibrato jack?

Thanks in advance!!

+ goes to pin 3 and - goes to the sleeve of the vibrato jack.

Title: Re: '69 Fender Bandmaster Reverb Capacitor Question
Post by: tomof63 on February 24, 2021, 05:26:52 pm

2deaf,

Thanks for the info! I had no doubt that some one here would know.