How To Repair Your Bic 940
Tom's BIC 940 Record Changer Repair Guide
Welcome to my webpage for those interested in getting their onetime BIC tape changers from the mid-1970s back in operation. They're cracking machines, but age has left many of them running poorly or not at all. I have been an electronics hobbyist and electronics technician specializing in audio equipment for many years. What I volition tell you here is particularly based on my experience with keeping a pair of Model 940s in operation. The same solutions to common problems will likely apply to other models in the line, equally well. In brusque, well-nigh all difficulties with the mechanical operation of these and other record players and changers are caused quite merely by oxidation. That is, the reaction of various organic compounds such every bit grease and rubber with the the temper over time, causing unwanted changes that uiltimately result in their not existence able to perform the task for which they were intended. Replace those deteriorated items with fresh ones and correct operation ordinarily resumes. Let'south wait at some mutual problems with the BIC Model 940 (and others) and how they may be solved. I should add that the mechanical parts I refer to are named by me according to their apparent function and may non stand for to the nomenclature used by the visitor in their literature. Someone has commented that the record size select lever is mis-identified in the photos, that information technology should be the ane with "steps" in it.
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Try rotating the platter by manus, as it should plough with only a slight effort. If great resistance is felt, do non forcefulness it as the lubricating grease has likely hardened. Sometimes, it can literally "turn to glue" and you don't desire to crusade any damage by spinning things that are meant to stay stationary (see terminal paragraph under this trouble). Regardless of the effect of your test, you'll need to remove the platter to diagnose the trouble furthur in the post-obit way:
1) Remove any tape spindle from the center by pulling it up.
2) Remove the blackness plastic snap band that holds the platter downwards. This can be done by using a pair of snap ring pliers bachelor at automobile parts stores, or with a pair of big newspaper clips that have had their ends bent at a ninety-degree bending about i/8 inch up. Either way, the idea is to hook the ii holes and spread the prune apart while lifting it upward and out of the groove information technology's in.
3) If the platter spins hands, simply lift information technology off. If it turns hard or not at all, yous'll need to soften the grease, offset. Do this past carefully applying penetrating oil, WD-40 or fifty-fifty lighter fluid or kerosene (from the acme) where the platter contacts the main bearing shaft. Let the lubricant penetrate for at least a half hour, try rotating the platter and employ more of the liquid if information technology is still tight. Echo this procedure until the platter can be removed.
You will notation that there is a belt (usually orange) that runs between an inner rim cast into the platter and the motor pulley. One side of the chugalug runs through a cerise plastic speed-changing guide that serves to motility the belt up or downward on the pulley, depending on the speed selected. I don't know what compound BIC used in their industry, but the 2 original belts in my record changers remain supple and reasonably taut, which is most unusual for a safety chugalug. With luck, yours will be, too. Go along the belt from contacting any lubricant and if it does, clean it thoroughly with a paper towel moistened with rubbing alcohol. While original belts are likely not bachelor, a workable substitute such as an FBM15.two should be able to exist plant online.
Now is the time to assess the condition of the original grease, even if your platter was spinning freely. Stacked at the lesser of the stationary shaft volition be the following items which should exist slid up the shaft and removed one at a fourth dimension, with the exception of the bottom washer:
(peradventure a black o-ring, if it's fallen off the bottom of the platter)
a smooth-surfaced washer
a ball bearing
a second shine-surfaced washer (go out there).
If the grease packed into the ball begetting has hardened, y'all'll need to remove all the old lubrication in this and on the washers, shaft and platter sleeve bearing (the hole upwardly through the platter). Employ any of the solvents mentioned before in conjunction with a toothpick, cotton swabs and a newspaper towel or ii to accomplish this task. One time the old grease has been removed, apply new lubricant and slide the bearing and superlative washer dorsum onto the shaft. Also lubricate the shaft and inner surface of the platter bearing using a cotton swab. A light grease is preferred, merely motor oil should also work. I wouldn't recommend a thin, household-type oil, though.
While the platter is off you can check the performance of the motor by connecting the ability cord and sliding the lever forrard to the "manual" position. If the pulley spins, it is probable okay. If not, you may have a bad switch or power cord that should be investigated. When turned by mitt with no power applied, the motor caster actually should non spin particularly freely, only rather, there should be some resistance--a sort of "cogging" effect due to the activity of the 24 magnetic poles within. If information technology turns really hard or seems frozen in place, you will need to attempt to costless the shaft. Equally this is a sealed, synchronous motor similar to those used in electric clocks for years, any repair will probable exist limited to working a tiny chip of WD-40 or the like into the top bearing underneath the pulley. If this helps free things up, follow it by an tiny application of very light oil in the aforementioned spot. I should add together here that the height of the pulley on the shaft seems to affect the platter speed to a certain degree. If a stroboscope indicates an slight discrepancy, endeavour moving the pulley upward or downwardly later loosening the setscrew. I call back a down movement increases the speed and an upward one decreases it. However, if the speed is especially slow it is more likely to exist a lubrication or chugalug result every bit addressed in this section, or mayhap a loose setscrew in the pulley. Be sure to tighten it securely.
I mentioned earlier the possibility of there being a blackness o-ring above the peak metallic washer. If at that place is, this likely came from around a groove at the lesser of the platter bearing, right beneath the geared portion. While non critical, I believe its purpose is to prevent the platter from spinning on meridian of the washer and possibly as a rumble (mechanically transmitted noise) dampener. As rubber tends to expand when in contact with hydrocarbons, you may discover that, while supple, the band has swelled to where information technology won't stay in position in the groove. If this is the case, you may want to supplant information technology with one of a slightly smaller diameter from your local hardware store or domicile center. Another o-ring that will likely demand to exist replaced is addressed in a subsequently section.
If it hasn't been done already, clean the chugalug past running it through a folded paper towel moistened with rubbing alcohol. Yous may also wish to clean the motor pulley and inner rim of the platter. To reassemble the platter, loop the chugalug around the inner rim and hold it taut, pulled toward the motor pulley with 2 fingers. Begin to slide the platter over the shaft, while at the same fourth dimension hooking the chugalug over the motor caster. This tin be a tricky thing to do and you lot may discover it necessary to enlist the services of a helper. You lot may wish instead to construct a tool from a human foot long slice of coathanger wire formed into a V. Bend the last quarter inch or then of the ii ends up at a 90-degree bending and use them, held apart, to pull the chugalug over the pulley. Later operating the record changer to see that all is in guild, the final pace is to replace the black plastic snap ring and so that the platter will remain in position when it is turned upside-down. Note that this has a tab that needs to be positioned in such a way that it fits in the groove that is made for it.
I should mention ane other thing, which I understand tin sometimes occur when the turntable platter has become "frozen" to the bearing and the whole assembly forcibly rotated. You lot'll know this has occured if the center stacking spindle turns along with the platter and at that place's a lot of "rumble" in the audio, or records aren't dropping properly because the spindle has been rotated out of its proper position. If this has occured, you'll demand to practise the disassembly and cleaning/lubrication mentioned above, as well as re-securing the center bearing in the appropriate position. When it is oriented correctly, the vertical groove in information technology (which accepts the pin on the stacking spindle) should confront most thirty degrees clockwise from the back of the mechanism. In this way, the "lip" of the record stacking spindle on which the records rest volition exist lined upward with, merely exactly 180 degrees reverse the record support in the corner. You'll probable need to cement the bearing in place, after thoroughly cleaning the area of whatsoever oily residue.
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This mutual problem is acquired by the hardening of a tiny (white) o-band on the reject lever. The function of this rubber o-ring is to supply a slight amount of friction betwixt itself and the metallic plate resting above it. When the tonearm reaches the end of the record the plate moves and slightly rotates the turn down lever, causing 1 finish to catch a protrusion on the outside of the platter bearing. This starts the chief gear rotating and the changer cycles. The friction created by the o-ring is necessary since the plate and lever cannot exist connected directly together - a certain amount of slippage is necessary. When the prophylactic hardens, too much slippage may result and the record won't reject. On the other hand, if the hardening tends to cement the o-band to the metallic the lack of slippage volition cause the tonearm to bounce back onto the record each fourth dimension it attempts to pass up.
I narrowly does not have to remove the primary mechanism gear in order to event a repair. Instead, do the following:
one) With the record changer turned upside down, carefully remove the circlip securing the shaft of the turn down lever and piece of work it out from underneath the red plastic gear. This may accept some fanagling.
2) Using 1 of the liquids mentioned before, clean all sometime lubricant from the shaft and bushing.
iii) Clean the surface of the metal plate where the o-band contacts it with a cotton swab moistened with rubbing alcohol.
iv) Pull the old o-ring off and supercede it with one measuring 11/32 10 7/32 x i/16, such every bit Danco stock no. 35761B.
5) Carefully wipe the reject lever's shaft with a small piece of paper towel moistened with a drop or two of very calorie-free oil. Do not over-lubricate!
half-dozen) Reinsert the lever dorsum through the metallic plate and the plastic gear. This may require the utilize of a pair of tweezers. Note the aptitude end of the lever must fit in the cutout in the plastic wheel. While holding the lever in position, re-install the circlip.
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This is another example of hardened grease interfering with proper mechanical performance. In this instance, it involves the lever that determines how far inward the tonearm moves, equally determined by the setting of the speed selector. Although a fair amount of disassembly is required to outcome a (hopefully) lasting cure, it is worth the endeavor as I can tell you from experience that simply applying new lubrication over old won't hold up. Here'southward what you need to do:
1) With the record changer upside down, remove from the post the following: circlip, bound, washer and minor metal piece and set them aside.
ii) Lift off the tonearm command lever.
three) Remove lower circlip and spring and set them aside. This volition permit y'all to elevator the metal levers enough to clean betwixt and beneath them.
4) Using cotton swabs moistened with ane of the hydrocarbon liquids mentioned before, thoroughly clean all the old lubricant from the levers and shaft around which they pivot. Also clean between the bottom of the record size select lever and the red plastic plate.
5) Using a cotton fiber swab moistened with a light oil, re-lubricate the above areas.
6) Reassemble the parts in reverse club. Make certain the peg at the end of the tonearm command lever seats into the groove on the plastic gear.
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I'm non sure this is a common occurance, but I'll tell yous how to cure it should it happen. In that location is a spring-loaded clench on the top of the record support. This applies some downwardly pressure against the tape stack which, in conjunction with the weight of the records, keeps more than one disc from dropping at a time. However, when down to just ii records the pressure level may not e'er be sufficient. What I did on my two BIC 940 changers was to add a flake of liquid vinyl to the lip underneath the front edge of the clamp. This has the benefit of adding increased friction resistance against the meridian disc. Liquid vinyl is available at hardware stores and home centers, will likely be fabricated by Plasti-Dip and may exist sold in a small can as a liquid electrical tape. It is possible a caulk that retains a condom-like consistency could as well be used.
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Barring a mechanical issue nether the changer (such as a broken or bent function or one out of position), this is virtually likely the result of the record stacking spindle not existence inserted fully into the changer. Sometimes, when unloading played records, the spindle volition become pulled upward slightly. Check to be certain it is fully seated and cannot be spun around. There is a peg that fits in a slot that will prevent the latter from occuring when it's in its proper position. As well make sure the black plastic snap band is properly oriented with its tab in the slot, equally this helps lock in the spindle. If you notice the spindle rotating along with the turntable platter, you accept a loose centre bearing. See the last paragraph nether the commencement symptom, above, for the prepare.
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Source: http://metco-electronics.com/BIC/index.htm
Posted by: boyerssafteph1959.blogspot.com
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