Try Gand Music in Northfield. I haven't been there, or anywhere up there for a few years, but they used to have a couple great reel techs.
http://www.gand.com/
Here are all the authorized Tascam service centers in the Chicago area if you don't have any luck at Gand.
Repair Facility Type: GENERAL REPAIR
Business Name: ACCUTRACK RECORDING & SOUND CO
Address: 2462 E. OAKTON ST.
City: ARLINGTON HGTS.
State: IL
Zip: 60005
Phone: 847-437-6200
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Repair Facility Type: GENERAL REPAIR & DTRS
Business Name: DELTRONICS, LTD.
Address: 2911 N. HALSTED
City: CHICAGO
State: IL
Zip: 60657
Phone: 773-549-6635
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Repair Facility Type: GENERAL REPAIR
Business Name: ELECTRONIC ENGINEERS, INC.
Address: 2522 W. ARMITAGE
City: CHICAGO
State: IL
Zip: 60647
Phone: 773-227-2600
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Repair Facility Type: GENERAL REPAIR
Business Name: I C M CORP
Address: 9050 HELEN LANE
City: ORLAND PARK
State: IL
Zip: 60462
Phone: 708-403-2715
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Repair Facility Type: GENERAL REPAIR
Business Name: JUST SERVICE, INC.
Address: 2940 N. CLARK ST.
City: CHICAGO
State: IL
Zip: 60657
Phone: 773-871-7171
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Repair Facility Type: GENERAL REPAIR
Business Name: M R H AUDIO CONCEPTS
Address: 37340 N. PIPER LANE
City: LAKE VILLA
State: IL
Zip: 60046
Phone: 847-587-9661
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Repair Facility Type: GENERAL REPAIR & DTRS
Business Name: MIDWEST AUDIO
Address: 774 W. ALGONQUIN RD.
City: ARLINGTON HTS
State: IL
Zip: 60005
Phone: 847-640-1890
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Repair Facility Type: GENERAL REPAIR & DTRS
Business Name: MIDWEST DIGITAL SERVICES, INC.
Address: 10150 VIRGINIA AVE., STE. H
City: CHICAGO
State: IL
Zip: 60415
Phone: 708-448-7539
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Repair Facility Type: GENERAL REPAIR
Business Name: MIDWEST MUSIC MENDERS, INC.
Address: 1917 W FULLERTON
City: CHICAGO
State: IL
Zip: 60614
Phone: 773-276-3939
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Repair Facility Type: GENERAL REPAIR
Business Name: MRH Audio Concepts
Address: 37340 North Piper Lane
City: Lake Villa
State: IL
Zip: 60046
Phone: 847-587-9661