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wanders

I picked up a pair of Monitor 5s (assembly date is1987) from a thrift store yesterday. One cabinet and grill was in good condition, the second appeared to have been dropped, two corners had major damage. Additionally, on the damaged speaker, the clips holding the grill on were missing and the grill was attached to the cab with sheetrock screws; finally, there is a hole, about 1/2 inch in diameter drilled throught the back of the damaged speaker cabinet, looks like it was used as a mounting point. I was able to inspect the drivers on the better unit before buying, they were all shiny, clean, and intact. I took a chance and invested $20.

When I got home, I removed the grill from the damaged cabinet and the drivers looked good, just like the better unit. None of the **** or drilling did any permanent damage.

I tested the pair with my Hafler P-3000. The better unit sounds good (actually fantastic). The damaged unit had some souind problems. I removed all three components and the cross-over and inspected. No apparent damage. Replaced the components, reconnected, and tested again; tried both speaker circuits and switched the Polks, right and left. Again the better unit is fine, in the damaged unit, the tweeter works but the woofer is silent. Later today, I'll swap the cross-overs to eliminate those as the problem. But, googling around, I read that dropping a Polk often damages the driver.

Couple of questions, I really like the sound of the one speaker and would like to own the pair (main speakers are Bose 901-series 1). But the damaged cabinet will require repair and both cabs need re-veneering, I can do all of that. But, assuming the woofer is shot, can it be repaired, or must it be replaced? How much am I looking at? How much would these speakers be worth?

Appreciate any help.

dorokusai

I'd yank the good parts, toss the cabinets and look for another pair. After you buy a new driver, invest time and money into repairing the cabinets and possibly do other work, you're at the point at which they sell for in better condition than you'll end up having.

Since you'll have the parts removed, go ahead and upgrade the xovers since they're simple and quite cheap to do on that model. When you find a better pair, you'll have modified xovers ready to drop inside and immediately use.

fbm211

Did you try pushing on the mid driver to see if was frozen.?

DON73

When you push on the large driver the midrange driver should move. If it doesn't it is probably "frozen". If it does move take it out then use an ohmmeter to see if there is continuity from one connection to the other. If the meter shows OL it has a broken wire in the voice coil and if it shows 0.0 it has a short. These drivers show up on e-bay and the CP classifieds often for under $30. A CP member will probably be along soon with one. Why do the cabinets need new veneer? Are the corner bashes in the back or front? If they're on the back especially on the bottom they can be repaired so that they are not readily visible. There are excellent threads here on renovating M5s and M7s. If you just want a pair of nice Polk speakers you can find several but if you want to renovate these and enjoy bringing a pair of vintage speakers back to life get the midrange problem fixed then do a search here for the threads on redoing the 5s and 7s. I keep referring to geoff27's work on these but he does such a beautiful job you may get some encouragement from seeing what can be done to these.
Right now I'm working on some old AR and Advent speakers that I'll never get my money out of but I'm having a lot of fun doing it. Welcome and keep us posted!

wanders

fbm211 wrote: »

Did you try pushing on the mid driver to see if was frozen.?

Thanks for the advice. Throught moving various components between the two units, the damaged speaker is clearly faulty. The cone is frozen in place, will not flex. Also, I'm seeing that frozen magnets are not uncommon to these drivers; considering the fact that there is corner damage from an apparent drop, it all adds up.

I've decided to repair the speakers for a couple of reasons. First, I found a replacement driver on eBay (mw 6502) for $25 + $10 s/h. Second, I've been using Bose 901-1's for a long time; and I'm considering a major change. Using the Monitor 5B's will give me a chance to experiment with a different kind of sound before deciding on what to do with the Bose.

I'll swap out the bad driver; if I like the sound and want to keep the Monitors for a while, I'll repair and veneer the cabinets and put them beside the Bose for maybe 6 months. I can switch back and forth between different sources and types (hate to say "genres") of music. I can re-veneer and watco the cabinets pretty easily and in-expensively. Depending, I may re-cap the cross-overs if I think it will enhance sq. I'll check out the threads mentioned. If members are interested, I can post some progress pics; let me know.

Again, thanks for the information and assistance.