Project: STA-2100 (Realistic) #2

Super Noob

Super Member
Here goes another rebuild = just completed.

Many posts to follow.

Realistic STA-2100 (my 2nd one) - other unit is documented here too. This unit was my first purchase back into vintage gear.

Photo of the patient (before) - nice looking unit:
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Here is the operation parts list (for sharing):
https://drive.google.com/file/d/1-njSaSs3Uei86QucV449a-Bo2Jbttg0j/view?usp=sharing
 
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Tone Control Board Next:

Get out the video = film party. :biggrin:
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Plenty of Dexoit and Fade Lube on These Pots and Switches

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Tuner Board:

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Forgot After Pic = You will see the board during final pics.

No Alignment Required = Everything is Locked On Solid.
 
Amp Boards:
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Replaced the Trims / Double Diodes / Small Transistors.
992s matched (HFE) to 1%.

All Outputs and Transistor With Heat Sinks Re-Pasted.
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Main Filter Caps Next + Bypass:
(drilled out the old = makes for very easy installation of new)
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2.2 uF (Panasonic stacked film bypass caps)
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Testing:

Bias:
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(on target) Note = Left Amp is Clockwise to Increase Bias / Right Amp is Counter Clockwise

Offset:
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Bones:
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Some LEDs:
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How Does She Look:
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Listening to Now = L36.
Sounds Strong.
Maybe not as nice as the SX-1250, but is that really a fair comparison.
Am happy with the results.
2-2 on my 2100s.
My father-in-law has the other unit = cannot say I am not a good son-in-law.
 
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I have a nice 2100 that is fully functional, slight noise in the left channel until it warms up a little. I am in the process of gathering up all the parts - thanks for your list by the way!

I am fairly skilled at soldering, have a decent Weller iron and Hakko vacuum desoldering tool.

I am curious just how far you removed each board out of the receiver to work on it? Some of those boards are wire wrapped connections and I hate those - and I don't have the proper tools to reconnect once disconnected outside of soldering.

Any tips or traps I need to be aware of?

Thanks
Don
 
It is tight on some boards with lots of connectors that you need to label and take many pictures.

The amps come out completely so no problem there. I didn’t have to cut or desolder any boards on the recap. I work with the unit on the side and support boards when working on them. I typically turn the unit and not the boards. (preserving the wire wraps from breaking)

The heat sensing triple diodes are the only wires to be cut but mine I believe both where crimped with wire caps from the factory.

Not the easiest or hardest set I have done. I have recapped two both documented.

Take your time, use a DBT, verify each board before moving on.
 
Thanks for the fast reply. You mention use a DBT? What is a DBT?.

I figure start with the power supply. verify unit operation, then move on to the next board, powering on and verifying after each board. Sound right?

Thanks again. I will take many photos and label wires but will try not to disconnect them.
 
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