I have a topic of interest to me because I am the one who has done all of these things.
I have an MLA 2500, with far less than 100 total hours running time on it, that was for reasons I won't go into here, stored away in 1985 along with all the rest of the ham equipment. The tubes were removed and stored in the original shipping material they were received in from the selling vendor, Now here are the topics of discussion I would like to have some opinions about, what affect aside from possible cap drying will the electronics assembly suffer in such a long storage without ever having any voltage applied to them? Also, what if any affect will the super expensive and impossible to find tubes have suffered lying there in the foam and bubble wrap packing with nothing to do. I have seen the 8875's advertised with lots of hours but with good output listed for several hundreds of dollars and I assume those had been in use at least most of their lives. I have also seen discussions that advocated applying a lowered voltage to the circuits for an extended time to re-whatever the caps. Both the tubes in their languish and the chassis have been in a climate controlled environment, ie heated and air conditioned for the entire time.
I would like to hear from anyone who has more knowledge than I either through education or school of hard knocks.
Thanks and please be gentle it was not my idea to have to store it away for such a long time...
Stored equipment and how it is affected.
I am certainly no expert at this, but I have just completed a restoration of my old Ham shack from over 30 Years ago.
Unfortunately my old equipment was not stored in a nice environment, but in cardboard boxes in the basement.
I only attempted this task because some friends participated in the last field day and asked me to set up an old-fashion SWL station for the entertainment of the wives and guests who were not hams.
When I first looked at the equipment when it came out of the boxes, I gave up all hope of getting any of it to work ever again. The mold, mildew and corrosion looked horrible. I stripped everything out of the inside which was removable, tubes etc. I then went to work cleaning the chasis. While this was tedious, it turned out to be quite successful and most of the stuff came out with Alcohol soaked brushes and rags. A good contact cleaner was used in the tight spots.
After things looked pretty clean, I paid special attention to the tube sockets and they took a lot of contact cleaner which was soaked in with Q tips.
After a few tries, Things actually started to come back to life.
Out of a total of 6 Receivers and Two Transmitters, I was able to revive all but two Receivers, an old National 270 and a Realistc DX-300.
I believe I could resurrect the DX-300, but unfortunately I do not have the required Test equipment anymore.
To sum up, after the tedium of cleaning everything, I really did not encounter any serious problems except in the two cases mentioned.
Unfortunately I cannot give you the exact cause of these two failures for the reason mentioned above
I don't know if this helps or not, I just wanted to let you know what I encountered.
BTW, all my other equipment is Heathkit built many years ago and it is all in working condition again.
Adolph
Unfortunately my old equipment was not stored in a nice environment, but in cardboard boxes in the basement.
I only attempted this task because some friends participated in the last field day and asked me to set up an old-fashion SWL station for the entertainment of the wives and guests who were not hams.
When I first looked at the equipment when it came out of the boxes, I gave up all hope of getting any of it to work ever again. The mold, mildew and corrosion looked horrible. I stripped everything out of the inside which was removable, tubes etc. I then went to work cleaning the chasis. While this was tedious, it turned out to be quite successful and most of the stuff came out with Alcohol soaked brushes and rags. A good contact cleaner was used in the tight spots.
After things looked pretty clean, I paid special attention to the tube sockets and they took a lot of contact cleaner which was soaked in with Q tips.
After a few tries, Things actually started to come back to life.
Out of a total of 6 Receivers and Two Transmitters, I was able to revive all but two Receivers, an old National 270 and a Realistc DX-300.
I believe I could resurrect the DX-300, but unfortunately I do not have the required Test equipment anymore.
To sum up, after the tedium of cleaning everything, I really did not encounter any serious problems except in the two cases mentioned.
Unfortunately I cannot give you the exact cause of these two failures for the reason mentioned above
I don't know if this helps or not, I just wanted to let you know what I encountered.
BTW, all my other equipment is Heathkit built many years ago and it is all in working condition again.
Adolph
The most UNcommon thing in the world is common sense. !
long storage
"what affect aside from possible cap drying will the electronics assembly suffer in such a long storage without ever having any voltage applied to them? Also, what if any affect will the super expensive and impossible to find tubes have suffered lying there in the foam and bubble wrap packing with nothing to do."
Well I have brought back many older classic radios here and the other thing you will run into is the bandswitch wafer contacts will need to be totally cleaned with contact cleaner and possible pencil eraser on the stubborn contacts. Also you could use a sheet of loose leaf paper wetted with contact cleaner and pull it through the contacts. Another good method is a nice crisp dollar bill wetted with contact cleaner, don't pull it through too fast or you will leave some material where you don't want it. Dirty/oxidized contacts have been the number 1 problem I have run into with these older rigs, especially if stored away in humid/dusty areas, but also just sitting on the shelf in the so called controlled room. The suggestion of bringing up the power slowly with a variac is also a very good idea as most of the power supply caps will be dry and will look like just about a short circuit for a short time. Start at around 45Vac then gradually increase it to 60Vac and let it sit for 8hours, then bring it up to 90Vac for a time and then full 120Vac. The tubes should be ok as long as you stored them in their upright position and not on their sides. The grids will sag to one side if they were laid down sideways for long periods. Now some tubes were designed to be sideways like the 811A and the 572B, In that case store them on the opposite side they were operated at. The only way to test amplifier tubes is to apply full voltages and let em rip. If one has a shorted grid or filament, it will blow the fuse. Make sure all the fuses are of proper values for this reason or else you could blow a filament transformer or even a HV transformer and that would not be fun. So check all fuses for proper amperage ratings before operating the finals at full voltages. Good luck and oh, also watch for spiders...
Well I have brought back many older classic radios here and the other thing you will run into is the bandswitch wafer contacts will need to be totally cleaned with contact cleaner and possible pencil eraser on the stubborn contacts. Also you could use a sheet of loose leaf paper wetted with contact cleaner and pull it through the contacts. Another good method is a nice crisp dollar bill wetted with contact cleaner, don't pull it through too fast or you will leave some material where you don't want it. Dirty/oxidized contacts have been the number 1 problem I have run into with these older rigs, especially if stored away in humid/dusty areas, but also just sitting on the shelf in the so called controlled room. The suggestion of bringing up the power slowly with a variac is also a very good idea as most of the power supply caps will be dry and will look like just about a short circuit for a short time. Start at around 45Vac then gradually increase it to 60Vac and let it sit for 8hours, then bring it up to 90Vac for a time and then full 120Vac. The tubes should be ok as long as you stored them in their upright position and not on their sides. The grids will sag to one side if they were laid down sideways for long periods. Now some tubes were designed to be sideways like the 811A and the 572B, In that case store them on the opposite side they were operated at. The only way to test amplifier tubes is to apply full voltages and let em rip. If one has a shorted grid or filament, it will blow the fuse. Make sure all the fuses are of proper values for this reason or else you could blow a filament transformer or even a HV transformer and that would not be fun. So check all fuses for proper amperage ratings before operating the finals at full voltages. Good luck and oh, also watch for spiders...
BSET, GROL w/Ship Radar, A.R.S. W2CO
Getting them up and running again...
Greetings:
I restore old boat anchors and, as one might expect, some of the gear I receive to restore has been idle for years if not decades.
The good, the bad, and the ugly...
The Good. Tubes are glass and tungsten and if they do not have a vacuum leak, will not suffer from very long storage. I have seen tubes from the twenties come alive after being in stored in an old barn since before the "big war." As a matter of fact, the tubes fair better than most of the other components in the gear.
The Bad. Moisture is a killer of electronic equipment. Oxides usually are less conductive that their original metals so, if not stored in a dry environment, likely, there could be significant problems. The surfaces of all air capacitors will have be oxidized. The surface of pots and other physical contact controls can be contaminated. Use DEOXIT to clean these! Worst of all, rust can have invaded transformers, chokes, and other components. At the opposite end of the issue, a very hot or dry environment will have dried out grommets and other seals, including seals on capacitors and other components. Also, most plastic parts will have be made extremely brittle, including the plastic standoff insulators ans some of the old printed circuit boards.
The Ugly. Top of the line gear generally had high quality paint finishing but some manufactures used polymer finishes that, in time, become sticky and greasy feeling. Some bottom of the line products use cheap paints and those don't do well and all. Moisture invades the base metal from UNDER the paint and creates tunnels of rust. Other times, the paint just flakes off leaving the surface looking like it was out in a west Texas sand storm. Also, many plastics change color when stored where light can strike the surface. This even happens in older Collins equipment where the tuning dial has changed from white to a dingy ugly brown where it was left in the light. You know...Ugly.
Nice visiting...
K4ICL
I restore old boat anchors and, as one might expect, some of the gear I receive to restore has been idle for years if not decades.
The good, the bad, and the ugly...
The Good. Tubes are glass and tungsten and if they do not have a vacuum leak, will not suffer from very long storage. I have seen tubes from the twenties come alive after being in stored in an old barn since before the "big war." As a matter of fact, the tubes fair better than most of the other components in the gear.
The Bad. Moisture is a killer of electronic equipment. Oxides usually are less conductive that their original metals so, if not stored in a dry environment, likely, there could be significant problems. The surfaces of all air capacitors will have be oxidized. The surface of pots and other physical contact controls can be contaminated. Use DEOXIT to clean these! Worst of all, rust can have invaded transformers, chokes, and other components. At the opposite end of the issue, a very hot or dry environment will have dried out grommets and other seals, including seals on capacitors and other components. Also, most plastic parts will have be made extremely brittle, including the plastic standoff insulators ans some of the old printed circuit boards.
The Ugly. Top of the line gear generally had high quality paint finishing but some manufactures used polymer finishes that, in time, become sticky and greasy feeling. Some bottom of the line products use cheap paints and those don't do well and all. Moisture invades the base metal from UNDER the paint and creates tunnels of rust. Other times, the paint just flakes off leaving the surface looking like it was out in a west Texas sand storm. Also, many plastics change color when stored where light can strike the surface. This even happens in older Collins equipment where the tuning dial has changed from white to a dingy ugly brown where it was left in the light. You know...Ugly.
Nice visiting...
K4ICL