This is not (quite) a rant - but an attempt to pass on what little accumulated wisdom I have towards the sensitive subject of general repairs. What it is, is how I approach a new component, whether working or not, when it joins the herd. Note that a proper repair with thorough and cautions diagnostics will render a device that is perfectly reliable and fully operable. My office system has been operating for (at least) 5 hours per day, M-F, for weeks, now. And is no more than a collection of unmodified Dynaco tube products, but thoroughly checked and all marginal components replaced - like-for-like in value, but with generally higher-quality parts. I am quite content to leave it on while I am making my rounds.
This is in the general order of what I do:
Cleaning: Exterior:
a) high-proof Isopropyl alcohol, liberally applied, using soft cotton, lint free cloth.
b) Remove knobs and soak in hot soapy water (dish soap), and clean flutes with a toothbrush, if necessary. Note that hot water and Cream-of-Tarter will clean oxides from aluminum - but a light coat of lacquer afterward will prevent the corrosion from returning. Polishing is also an option.
c) Remove and clean face plate as above.
d) NOTE: At this stage, I generally do not focus on cosmetics other than those as may also be structural. They may wait until later when any repairs are completed and successful. And, after all, one does not "hear" a rusty cover.
Cleaning: Interior:
a) Clean all switches, pots and controls with a no-residue contact cleaner. Exercise while cleaning.
b) Follow up with a lubricating cleaner appropriate to the use.
c) With a vacuum cleaner, soft brush, Q-Tips and alcohol as above, remove any dust on the inside. Do this with extreme care and caution. Care not to damage components, caution not to expose yourself to any contaminants - more on this later.
Visual Inspection:
a) Inspect for burn marks, damaged components, broken traces, cracked caps/resistors/tubes. Use a magnifying glass under very good light to do so.
b) Compare to OEM schematic for anything that may have been changed/upgraded/repaired. Piece-by-piece.
c) Using a dental pick or similar fine-pitch device. check *EVERY* connection.
First power-up:
a) Using a metered variac, and with careful attention to the Ammeter, apply power over a minimum 45-second interval.
b) If the device uses a tube rectifier, there will be a linear ramp-up until the rectifier tube starts to pass DC.
c) Then, there will be a slow, but predictable jump in current which should stop at/below nameplate of the device.
d) If it goes the slightest bit above nameplate shut down immediately, knowing you will need filter caps (at least).
e) If it behaves properly at this stage, then shut down and hook it up for signal.
f) It will either pass signal, or it will not. If it does are there any audible artifacts - hum/hiss/buzz?
g) If no artifacts, if current use is within common sense, and there are no clicks/pops when cycling controls (they are all clean, remember), you are pretty much home-free at this point and need do more only by choice.
h) If artifacts, what is the nature? Hum (60 HZ) is typically a bad rectifier. Hum (120 HZ) is (are) typically (a) bad filter cap(s). Hisses are typically bad or leaky small-value caps. Buzzes and pops are likely tube-related, but not always.
i) Information from the above will help you with next-steps.
Never dive into a repair without a plan. Step-by-step and with specific goals. These plans may change on-the-fly based on uncovered conditions, but you must have it going in, or there will be inevitable problems.
FIRST RULE of repairs: One step at a time.
SECOND RULE: Test to the extent possible after each repair-step.
THIRD RULE: Take many pictures, make many sketches, take notes. Label wires from-and-to-where.
When removing a part, do so carefully. De-soldering can be a real PITA, but should be practiced to the extent possible. But, there is no shame in replacing wires altogether to avoid this. If one looks in old Dynaco Assembly manuals, the wire-strippers shown are the type that often score the copper - rendering a weak-point that all-to-often cracks over the years. And, those of you who have done this over time will find at least one such condition in just about every piece of Dynaco kit as they find. Solid wire is readily available, and tinned solid wire is ideal, albeit more costly.
https://www.newark.com/belden/8824/hook-up-wire-dispenser-kit-20awg/dp/36F181?gclid=Cj0KCQiA3b3gBRDAARIsAL6D-N9mVFEY7FhFX03iUBz4hIIeipSn_XIyrvL-3HOHnZp5J8znvmfbfe4aAiVZEALw_wcB&gross_price=true&mckv=szCDoAit4_dc|pcrid|81515566341|plid||kword||match||slid||product|36F181|pgrid|20376566541|ptaid|pla-162178067781|&CAWELAID=120185550001059966&CAGPSPN=pla&CAAGID=20376566541&CMP=KNC-GUSA-GEN-SHOPPING-Cable&CATCI=pla-162178067781
Preserve the old part until the new one is in-place and tested. It serves as a visual check and aide-memoire.
All circuit-boards should be retained, and if possible, restored before putting them away. Or, offered here, then eBay to other user/collectors.
If purchasing new boards (this is a strong personal preference), try to purchase them as blank-boards+parts, not as fully assembled modules. As such, if an error is made assembling the board, it will be yours and traceable. Not someone else's and a complete mystery.
Be methodical - ONE STEP AT A TIME.
Take frequent breaks.
Don't second-guess yourself. Your first instinct is usually the best.
Have excellent light (I have no less than four (4) articulated lamps over the bench, including a magnifier and a point-focused).
If stumped, walk away - Minimum 24 hours. FULL STOP!
About covers it.
On the "More Later" part - this is a post I revise and send out each spring on the vintage radio/audio groups that I frequent. Contains graphic images.
All:
I have changed the format a bit, and put all the links at the beginning.
Sorry for it being a bit late - but the information still applies.
http://www.nwf.org/~/media/PDFs/Global-Warming/Reports/They-Came-From-Climate-Change-WEB.ashx
https://entomology.ca.uky.edu/ef631
https://www.cdc.gov/hantavirus/surveillance/
http://bugguide.net/node/view/475348
https://www.cdc.gov/rodents/diseases/direct.html
https://www.cdc.gov/ncezid/dvbd/
https://ee_ce_img.s3.amazonaws.com/cache/ce_img/media/remote/ce_img/https_ee_channel_images.s3.amazonaws.com/article-figures/12582/article-g02_400_301.jpg
http://www.medicalnewstoday.com/releases/61646.php
images.radiopaedia.org/images/1827647/6b765cac7f64a5107b54df2e031e12.jpg
It is time for the annual post on stalking the wild radio (or other collectibles) - and what accidental passengers that may come along with it:
1. Insects and other arthropods:
Anything from spiders to wasps to fleas and more. Any radio that has spent substantial time in a barn, basement, shed, garage or any other damp or exposed area may well be inhabited by or infested with various small and potentially painful critters. Especially those found in the southern states, home to the Brown Recluse and Black Widow spiders. Wasps, centipedes (quite poisonous as it happens) and other vermin are no fun as well. And, if you do find some critter of this nature, KILL IT. Being soft-hearted and releasing it into _your_ environment may make you feel all warm and fuzzy, but that creature may then cause considerable harm being somewhere it does not belong and where it perhaps has no natural predators. EDIT: Global Warming (whether you believe in it or not) has pushed the Recluse range into southern Maryland – mostly by human transport and not as successful breeding colonies but more and more common, with some few transported by human agency as far as Michigan and Pennsylvania. This is one NASTY spider with a very nasty bite.
2. Evidence of Rodent Inhabitation: Handle with GREAT care.
Hanta-Virus (a relative of Ebola) is endemic throughout the entire United States, Mexico and parts of Canada. It is a disease without effective treatment and an over 50% mortality rate worldwide (36% in
the US). It is carried in the feces and fresh urine of many rodents...and there is limited recent evidence that reconstituted waste (dried but inhaled) will also spread the disease especially if inhaled, a
possibility not accepted in the recent past.
Lyme Disease: Carried by deer ticks that winter over in the white-footed deer mouse (an omnivore, BTW) that will winter over anywhere it can find shelter. The ticks that mice carry will leave the mouse
to lay eggs... perhaps in that radio that served as their temporary winter dorm and latrine. Various other tick-borne diseases include Rocky Mountain Spotted Fever, and a whole bunch more *very* nasty diseases not worth risking, are all endemic in the US.
Note that per the CDC, there are now four types of ticks carrying multiple diseases dangerous to humans and pets. All this flying back and forth with pet animals has made the problem massively worse.
3. Bird Dung & Old Nests: Per a recent paper, there have been over sixty (60) diseases that may be carried in wild bird poop including Avian Flu, Fowl Typhoid, Infectious Coryza, Paratyphoid, Salmonellosis, Schistosomiasis, strep and on-and-on. ((Those of you servicing your Bluebird and other bird houses about now need also keep this in mind.)) Most wild birds are carriers of these diseases and show no visible symptoms. We bleach our birdhouses - THEN we clean them out. Amazing the number of dead insects and other vermin we get out of them every spring.
Asbestos: Dangerous only when friable - small particles able to become airborne easily. If you are a smoker, even more dangerous. A single (one (1) fiber can cause a fatal reaction over time – although that actuality is extremely rare and will (usually) take many years. For all that, it is fairly easily made safe with a little bit of care and caution. But even if you do not believe it is dangerous, you do not have the right to expose others, or transport it in conveyances where residual material may come in contact with others - that is, do not transport it openly in the family minivan.
Bottom line: A proverbial ounce of caution beats the hell out of a pound of care. Common sense, rubber gloves, a breathing mask, Lysol, Bleach, Moth-balls, Insecticides (which often do not work on Spiders or Ticks, so read the label), and other elementary precautions conscientiously and carefully applied will "safen" even the nastiest of wild radios.
This is in the general order of what I do:
Cleaning: Exterior:
a) high-proof Isopropyl alcohol, liberally applied, using soft cotton, lint free cloth.
b) Remove knobs and soak in hot soapy water (dish soap), and clean flutes with a toothbrush, if necessary. Note that hot water and Cream-of-Tarter will clean oxides from aluminum - but a light coat of lacquer afterward will prevent the corrosion from returning. Polishing is also an option.
c) Remove and clean face plate as above.
d) NOTE: At this stage, I generally do not focus on cosmetics other than those as may also be structural. They may wait until later when any repairs are completed and successful. And, after all, one does not "hear" a rusty cover.
Cleaning: Interior:
a) Clean all switches, pots and controls with a no-residue contact cleaner. Exercise while cleaning.
b) Follow up with a lubricating cleaner appropriate to the use.
c) With a vacuum cleaner, soft brush, Q-Tips and alcohol as above, remove any dust on the inside. Do this with extreme care and caution. Care not to damage components, caution not to expose yourself to any contaminants - more on this later.
Visual Inspection:
a) Inspect for burn marks, damaged components, broken traces, cracked caps/resistors/tubes. Use a magnifying glass under very good light to do so.
b) Compare to OEM schematic for anything that may have been changed/upgraded/repaired. Piece-by-piece.
c) Using a dental pick or similar fine-pitch device. check *EVERY* connection.
First power-up:
a) Using a metered variac, and with careful attention to the Ammeter, apply power over a minimum 45-second interval.
b) If the device uses a tube rectifier, there will be a linear ramp-up until the rectifier tube starts to pass DC.
c) Then, there will be a slow, but predictable jump in current which should stop at/below nameplate of the device.
d) If it goes the slightest bit above nameplate shut down immediately, knowing you will need filter caps (at least).
e) If it behaves properly at this stage, then shut down and hook it up for signal.
f) It will either pass signal, or it will not. If it does are there any audible artifacts - hum/hiss/buzz?
g) If no artifacts, if current use is within common sense, and there are no clicks/pops when cycling controls (they are all clean, remember), you are pretty much home-free at this point and need do more only by choice.
h) If artifacts, what is the nature? Hum (60 HZ) is typically a bad rectifier. Hum (120 HZ) is (are) typically (a) bad filter cap(s). Hisses are typically bad or leaky small-value caps. Buzzes and pops are likely tube-related, but not always.
i) Information from the above will help you with next-steps.
Never dive into a repair without a plan. Step-by-step and with specific goals. These plans may change on-the-fly based on uncovered conditions, but you must have it going in, or there will be inevitable problems.
FIRST RULE of repairs: One step at a time.
SECOND RULE: Test to the extent possible after each repair-step.
THIRD RULE: Take many pictures, make many sketches, take notes. Label wires from-and-to-where.
When removing a part, do so carefully. De-soldering can be a real PITA, but should be practiced to the extent possible. But, there is no shame in replacing wires altogether to avoid this. If one looks in old Dynaco Assembly manuals, the wire-strippers shown are the type that often score the copper - rendering a weak-point that all-to-often cracks over the years. And, those of you who have done this over time will find at least one such condition in just about every piece of Dynaco kit as they find. Solid wire is readily available, and tinned solid wire is ideal, albeit more costly.
https://www.newark.com/belden/8824/hook-up-wire-dispenser-kit-20awg/dp/36F181?gclid=Cj0KCQiA3b3gBRDAARIsAL6D-N9mVFEY7FhFX03iUBz4hIIeipSn_XIyrvL-3HOHnZp5J8znvmfbfe4aAiVZEALw_wcB&gross_price=true&mckv=szCDoAit4_dc|pcrid|81515566341|plid||kword||match||slid||product|36F181|pgrid|20376566541|ptaid|pla-162178067781|&CAWELAID=120185550001059966&CAGPSPN=pla&CAAGID=20376566541&CMP=KNC-GUSA-GEN-SHOPPING-Cable&CATCI=pla-162178067781
Preserve the old part until the new one is in-place and tested. It serves as a visual check and aide-memoire.
All circuit-boards should be retained, and if possible, restored before putting them away. Or, offered here, then eBay to other user/collectors.
If purchasing new boards (this is a strong personal preference), try to purchase them as blank-boards+parts, not as fully assembled modules. As such, if an error is made assembling the board, it will be yours and traceable. Not someone else's and a complete mystery.
Be methodical - ONE STEP AT A TIME.
Take frequent breaks.
Don't second-guess yourself. Your first instinct is usually the best.
Have excellent light (I have no less than four (4) articulated lamps over the bench, including a magnifier and a point-focused).
If stumped, walk away - Minimum 24 hours. FULL STOP!
About covers it.
On the "More Later" part - this is a post I revise and send out each spring on the vintage radio/audio groups that I frequent. Contains graphic images.
All:
I have changed the format a bit, and put all the links at the beginning.
Sorry for it being a bit late - but the information still applies.
http://www.nwf.org/~/media/PDFs/Global-Warming/Reports/They-Came-From-Climate-Change-WEB.ashx
https://entomology.ca.uky.edu/ef631
https://www.cdc.gov/hantavirus/surveillance/
http://bugguide.net/node/view/475348
https://www.cdc.gov/rodents/diseases/direct.html
https://www.cdc.gov/ncezid/dvbd/
https://ee_ce_img.s3.amazonaws.com/cache/ce_img/media/remote/ce_img/https_ee_channel_images.s3.amazonaws.com/article-figures/12582/article-g02_400_301.jpg
http://www.medicalnewstoday.com/releases/61646.php
images.radiopaedia.org/images/1827647/6b765cac7f64a5107b54df2e031e12.jpg
It is time for the annual post on stalking the wild radio (or other collectibles) - and what accidental passengers that may come along with it:
1. Insects and other arthropods:
Anything from spiders to wasps to fleas and more. Any radio that has spent substantial time in a barn, basement, shed, garage or any other damp or exposed area may well be inhabited by or infested with various small and potentially painful critters. Especially those found in the southern states, home to the Brown Recluse and Black Widow spiders. Wasps, centipedes (quite poisonous as it happens) and other vermin are no fun as well. And, if you do find some critter of this nature, KILL IT. Being soft-hearted and releasing it into _your_ environment may make you feel all warm and fuzzy, but that creature may then cause considerable harm being somewhere it does not belong and where it perhaps has no natural predators. EDIT: Global Warming (whether you believe in it or not) has pushed the Recluse range into southern Maryland – mostly by human transport and not as successful breeding colonies but more and more common, with some few transported by human agency as far as Michigan and Pennsylvania. This is one NASTY spider with a very nasty bite.
2. Evidence of Rodent Inhabitation: Handle with GREAT care.
Hanta-Virus (a relative of Ebola) is endemic throughout the entire United States, Mexico and parts of Canada. It is a disease without effective treatment and an over 50% mortality rate worldwide (36% in
the US). It is carried in the feces and fresh urine of many rodents...and there is limited recent evidence that reconstituted waste (dried but inhaled) will also spread the disease especially if inhaled, a
possibility not accepted in the recent past.
Lyme Disease: Carried by deer ticks that winter over in the white-footed deer mouse (an omnivore, BTW) that will winter over anywhere it can find shelter. The ticks that mice carry will leave the mouse
to lay eggs... perhaps in that radio that served as their temporary winter dorm and latrine. Various other tick-borne diseases include Rocky Mountain Spotted Fever, and a whole bunch more *very* nasty diseases not worth risking, are all endemic in the US.
Note that per the CDC, there are now four types of ticks carrying multiple diseases dangerous to humans and pets. All this flying back and forth with pet animals has made the problem massively worse.
3. Bird Dung & Old Nests: Per a recent paper, there have been over sixty (60) diseases that may be carried in wild bird poop including Avian Flu, Fowl Typhoid, Infectious Coryza, Paratyphoid, Salmonellosis, Schistosomiasis, strep and on-and-on. ((Those of you servicing your Bluebird and other bird houses about now need also keep this in mind.)) Most wild birds are carriers of these diseases and show no visible symptoms. We bleach our birdhouses - THEN we clean them out. Amazing the number of dead insects and other vermin we get out of them every spring.
Asbestos: Dangerous only when friable - small particles able to become airborne easily. If you are a smoker, even more dangerous. A single (one (1) fiber can cause a fatal reaction over time – although that actuality is extremely rare and will (usually) take many years. For all that, it is fairly easily made safe with a little bit of care and caution. But even if you do not believe it is dangerous, you do not have the right to expose others, or transport it in conveyances where residual material may come in contact with others - that is, do not transport it openly in the family minivan.
Bottom line: A proverbial ounce of caution beats the hell out of a pound of care. Common sense, rubber gloves, a breathing mask, Lysol, Bleach, Moth-balls, Insecticides (which often do not work on Spiders or Ticks, so read the label), and other elementary precautions conscientiously and carefully applied will "safen" even the nastiest of wild radios.