Your case will be little tricky,
If you don't want spend money to replace the electronic filter. Suggest you to measure the size of the filter, Height x Width x Depth. Build a wooden box with the measurement then buy a next size down filter fit it into the wooden box. Understand?
By the way. What is wrong of the electronic filter? It seldom any thing will be wrong, it is a very simple device………it used electrical current that general a + and – electron to attract the dust as it going though, Clean it, Dry it, and Use it again…
If you don't want spend money to replace the electronic filter. Suggest you to measure the size of the filter, Height x Width x Depth. Build a wooden box with the measurement then buy a next size down filter fit it into the wooden box. Understand?
By the way. What is wrong of the electronic filter? It seldom any thing will be wrong, it is a very simple device………it used electrical current that general a + and – electron to attract the dust as it going though, Clean it, Dry it, and Use it again…