Should I repair or replace my Wurlitzer 200 or 200a amplifier?

206a lid schematic.jpg

After restoring Wurlitzer electronic pianos for over a decade, we have seen amplifiers in varying condition, ranging from pristine to biohazardous. Sometimes we repair the amps, and sometimes we just replace them.

If your Wurlitzer 200 (200a, 203, 206, 206a, 210 or 214) is starting to crackle, buzz, hum, or pop, it may be time to take a look at it’s amplifier. And having a fully functional amplifier in your Wurly is essential to keeping it happy: after all, it is an electronic piano. Smooth, piano-like action is only half of what make Wurlitzers so fun to play. They also need to be amplified and the amp plays an important role in the instrument’s tonal splendor. 

If you have determined that the amplifier is the cause of your noise problems, you may be wondering: can I repair my amp, or should I replace with one of the currently available amp reproductions? The answer is yes you can, and maybe you should.  

Let’s take a look at the indicators that say “Replace, don’t repair.” 

signs of an amp that definitely must be replaced

Cracks in the circuit board. This may sound obvious, but if you visually inspect the amp board and notice cracks in the plastic, these are cracks that will go right through to the circuit leads. This is a sign that you should seek a replacement.  Cracks that break through the contacts of the printed circuit are pretty much deal-breakers with only crude work-around repairs.  

Infestation and mouse nests. Gross, but we’ve seen it so often we’re actually losing count.  Mice (and bugs, specifically cockroaches) love the safe fortress-like interiors of Wurlitzers and bring a vast range of nest materials in with them.  They also bring food and leave droppings, sometimes right smack in the middle of the board.  This kind of waste is unsafe and damaging. Cleaning up rodent droppings requires you to first spray the entire area with detergent, so you don’t kick up aerosolized mouse poo dust as soon as you wave a rag over it. This is obviously not great for the electronics. So, if your board is a literal rat’s nest it should be tossed.  This is a little more common in 206 (as well as 214, 203 & 210 models) as the consoles offer more ways into the instrument. 

Previous repairs good or bad. If the amp isn’t working and the board was worked on before (or many times before), your Wurlitzer may be ready for a replacement amp.  If you are comfortable taking out the board and looking underneath and inspecting the leads, look for smoked-out component holes or flaking printed circuit.  The printed circuit is fragile and becomes even moreso with age.  Heat from a soldering iron or hot components can jeopardize the thin board circuit and make repair difficult and fruitless.  

Basically, any damage to the circuit board, or any damage that is widespread across the amp, means that you should definitely replace your Wurlitzer’s amp with a new one. Think of it this way: the circuit board alone is unobtainable, while all of the parts on it are widely available and inexpensive. You could probably replace all the components for around $60. However, the heat that is required to remove all of the old components and install new ones is very likely to damage the circuit board. This is why you should weigh the number of components that should be replaced against the risk of hurting the board structure. If your repair looks likely to become extensive, you’ll probably have better results replacing the entire amp.

However, most amps won’t have such dramatic and extensive damage. What if your amp is just a little bit broken? Should you try to fix it, or should you install a brand new amplifier?

BORDERLINE ISSUES THAT COULD BE FIXED (NEW AMP OPTIONAL)

A new amp has a lot of benefits. Most notably, it makes your Wurlitzer more reliable, so you can depend on it during crucial performing or recording scenarios. But if you’d prefer keeping the amp original, at least for now, here are some problems that are not necessarily a death sentence for your Wurlitzer’s electronics:

No sound. Believe it or not, just because your Wurlitzer isn’t passing sound doesn’t mean that the amp is dead. In fact, it might be due to a problem outside of the amplifier, in which which case the problem will persist once the new amp is installed. For this reason, it will save you a lot of frustration if you figure out why your Wurlitzer is not passing sound before you invest in a new amp. (More on that below.)

Any problem related to low volume, odd sounds, or hum, if the amplifier is completely original. If your amp is completely original, that means it still has the original electrolytic capacitors. Electrolytic caps dry out over the years and can cause the amp to hum or otherwise behave in unusual ways. Replacing all of the original electrolytics is a routine fix, and it often solves a lot of problems. However, bad electrolytics may not be the only problem - or, rarely, an electrolytic can fail in a way that takes out other components. So, if you have the time and the inclination, you could try replacing the electrolytics before replacing the entire amp. Just note that new electrolytics aren’t a cure-all, and your particular amp might need further work.

What if the amp has low volume, odd sounds, or hum, and it isn’t completely original? Sometimes, you’ll see evidence of prior repair in a broken amp. This either means that a) someone successfully repaired it a while ago, and it subsequently broke for a reason unrelated to the quality of the repair; b) someone tried to repair it, failed and gave up; or c) someone tried to repair/mod the amp and did a terrible job and now it’s extra broken. Evidence of prior repair doesn’t mean that the amp is unfixable, but it does add an extra step because now you have to analyze what the previous repairperson did.

Problems that a New Amp Won’t Fix

Obviously, if your Wurlitzer’s problems had nothing to do with the old amp, installing a new amp won’t fix them. There are a handful of issues that would seem amp-related but are not, including:

  1. A bad power transformer (low volume, no volume)

  2. Blown speakers (distortion)

  3. Shorted or dirty reed bar (no volume, distortion)

  4. Dirty or degraded input jack (no volume, intermittent volume, distortion)

  5. Degraded or disconnected wiring (no volume, hum)

And while you are replacing, installing all new leads to the volume, vibrato and speakers is suggested.  

If your board exhibits none of the symptoms listed above and looks damage-free, you can likely replace the failing components that are causing noise and have satisfying results.  Just remember that 50 year old circuit boards don’t like the heat of soldering irons so brief and concise component replacement is key. 


Further Reading

Browse all of our articles on restoring vintage gear. Or, click on an image below.


Paulina Salmas