Killer Looks - Motorola 57H!
This is the dream model for me - beautiful, iconic, rare, very collectible. This is one of the model designs that lit the fire in my belly for this hobby.
Also, sounds great!
Motorolas of the late 50s are very well made with quality components. I will go through that in a moment. Of all the radio manufacturers from the 50s, Motorola is one of the few that's still around.
This particular 57H has been sitting around my vault for quite some time. I savor repairing and restoring these! This one came to me from a collection with a bunch of other 57Hs.
For me, the rare colors are most appealing. So, this one in sea green is one of my favorites.
This one had no chips. There are two heat cracks in the usual place on the top by the left back over the amplifier tube which gets the hottest.
This one had nice knobs that have not yellowed much:
The little gold metal ring is designed to tension the clear cone so it doesn't pop off.
The power cord interconnect was in good shape on this one. These cords usually suffer from wear fatigue at the base interconnect.
This circuit board does not show any signs of previous repair service. It looks all original.
The left three tubes 50C5, 12BA6, 12AV6 might be factory original tubes even. I wonder why there is electrical tape over one of the IFTs. The aluminum covered filter capacitor are far better quality than the beeswax ones. This is one is still good after all these years. No hum.
The solder joints to the antenna that usually break off over the years appear to be original. I like to preserve originality whenever possible. I try to handle the repairs very delicately with minimal movement to the sub assemblies (i.e. circuit board, antenna, power, speaker, etc) so solder joints aren't weakened resulting in need to reflow. This makes repairs take longer but solder joint originality is maintained.
I use a special circuit board cleaner that doesn't leave a thick deposit. I use a set of specialized cleaning brushes to get into the nooks and crannies where dust and dirt are difficult to remove. The tuning string gets loose over time and needs to be retensioned to avoid slippage. You must be very careful not to scratch the tuning cone.
The speaker on this one was in excellent condition with not buzzing or rattling. Looks new!
The clear nose cone was one of the better ones with few scratches and no broken off mounting notches.
After a steam clean, the cabinet came back looking great!
No broken solder joints during the restore process! Just two capacitors needed to be replaced. All circuit voltages and tolerances within factory spec! After that, tubes tested good and alignment performed.
Here's what it looks like reassembled and serviced!
Onto machine then hand polish