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Pioneer ER-420 Receiver

David_NC

David_NC

Super Member
I picked this up recently, along with a much older Pioneer SM-B201. Cosmetically, it looks really good, especially for its age, and all parts are present.
ER-420 -1.jpeg Top.jpg
I recently recapped and replaced a few other parts on a Dynaco ST-70, so I thought this might be a fun project... until I looked at the bottom:
Bottom - main.jpg
This thing looks crazy complex, or are tube receivers usually this 'busy' on the underside? Obviously, I realize it will be more involved than a power amp or other separates. Looking closely, it appears if one cap is much newer than the others, but I'd say that all the other caps and resistors look to be original. There's a multi cap and two larger caps on the upper deck of the amp, too.
I guess I'm wondering if this is par for the course for a tube receiver. I think it'd be nice to have this for a smaller system, and its appearances are so good that I could see using it. However, I'd like to keep it reasonable, in terms of cost, which means doing at least much of the work myself. I know all the gray caps need to go, but how about the flat ones and large resisitors?
There are a few components I've not seen before... I'd guess they are some sort of resistor:
Bottom 2.jpg

Here are some general pics:
Bottom - Bad Cap.jpg Bottom - Diodes.jpg Bottom - Suzuki.jpg Tubes.jpg

Any thoughts, input, experience, or ideas on this would be appreciated.
 
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Leave the flat caps and large resistors alone. Yup, all those Suzuki caps gotta go and yes, those things are usually pretty tight underneath but that thing is nothing compared to my Sansui 1000A tube receiver. :no:

Those clear / semi green things are also capacitors or coupling capacitors.
 
Last edited:
century tek said:
Leave the flat caps and large resistors alone. Yup, all those Elna caps gotta go and yes, those things are usually pretty tight underneath but that thing is nothing compared to my Sansui 1000A tube receiver. :no:

Those clear / semi green things are also capacitors or coupling capacitors.
Click to expand...

I guess all the Suzukis gotta go, too. Are the green / clear caps OK to leave? My thoughts are to get this thing safe to at least power on and check before doing any more work. In a few places, it looks like the caps were put in first and then covered with all other components. I can tell that I'll likely have to use the leads from the original caps as solder points for the new ones (here are a couple with red marks on them).
Buried Caps.JPG
Most of it looks pretty straightforward and shouldn't be prohibitively expensive. Time to work up a parts list, I suppose! Thanks.
 
Tube stuff is busy, Japanese tube stuff is worse than most though. Layout makes a huge difference in how annoying things are to work on.

The clear caps are probably OK. those are usually polystyrene. Its durable, but keep heat away from them or they drift or fail. Try to avoid even touching the leads wit the iron if possible, and if you do have to heat the lead, use a clip or something as a heat sink.

WHat I'd be concerned with most are the electrolytic caps and the grey oil capacitors.
 
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